diff --git a/cps/db.py b/cps/db.py
index 2e428f72..8b8db10a 100644
--- a/cps/db.py
+++ b/cps/db.py
@@ -609,7 +609,8 @@ class CalibreDB():
             randm = self.session.query(Books) \
                 .filter(self.common_filters(allow_show_archived)) \
                 .order_by(func.random()) \
-                .limit(self.config.config_random_books)
+                .limit(self.config.config_random_books) \
+                .all()
         else:
             randm = false()
         off = int(int(pagesize) * (page - 1))
diff --git a/cps/helper.py b/cps/helper.py
index 0b0c675f..c33a69e1 100644
--- a/cps/helper.py
+++ b/cps/helper.py
@@ -533,6 +533,21 @@ def delete_book(book, calibrepath, book_format):
         return delete_book_file(book, calibrepath, book_format)
 
 
+def get_thumbnails_for_books(books):
+    books_with_covers = list(filter(lambda b: b.has_cover, books))
+    book_ids = list(map(lambda b: b.id, books_with_covers))
+    return ub.session\
+        .query(ub.Thumbnail)\
+        .filter(ub.Thumbnail.book_id.in_(book_ids))\
+        .filter(ub.Thumbnail.expiration > datetime.utcnow())\
+        .all()
+
+
+def get_thumbnails_for_book_series(series):
+    books = list(map(lambda s: s[0], series))
+    return get_thumbnails_for_books(books)
+
+
 def get_cover_on_failure(use_generic_cover):
     if use_generic_cover:
         return send_from_directory(_STATIC_DIR, "generic_cover.jpg")
@@ -558,6 +573,29 @@ def get_cached_book_cover(cache_id):
     return get_book_cover_internal(book, use_generic_cover_on_failure=True, resolution=resolution)
 
 
+def get_cached_book_cover_thumbnail(cache_id):
+    parts = cache_id.split('_')
+    thumbnail_uuid = parts[0] if len(parts) else None
+    thumbnail = None
+    if thumbnail_uuid:
+        thumbnail = ub.session\
+            .query(ub.Thumbnail)\
+            .filter(ub.Thumbnail.uuid == thumbnail_uuid)\
+            .first()
+
+    if thumbnail and thumbnail.expiration > datetime.utcnow():
+        cache = fs.FileSystem()
+        if cache.get_cache_file_path(thumbnail.filename, fs.CACHE_TYPE_THUMBNAILS):
+            return send_from_directory(cache.get_cache_dir(fs.CACHE_TYPE_THUMBNAILS), thumbnail.filename)
+
+    elif thumbnail:
+        book = calibre_db.get_book(thumbnail.book_id)
+        return get_book_cover_internal(book, use_generic_cover_on_failure=True)
+
+    else:
+        return get_cover_on_failure(True)
+
+
 def get_book_cover_internal(book, use_generic_cover_on_failure, resolution=None):
     if book and book.has_cover:
 
diff --git a/cps/jinjia.py b/cps/jinjia.py
index bf81c059..b2479adc 100644
--- a/cps/jinjia.py
+++ b/cps/jinjia.py
@@ -139,3 +139,19 @@ def book_cover_cache_id(book, resolution=None):
     timestamp = int(book.last_modified.timestamp() * 1000)
     cache_bust = str(book.uuid) + '_' + str(timestamp)
     return cache_bust if not resolution else cache_bust + '_' + str(resolution)
+
+
+@jinjia.app_template_filter('get_book_thumbnails')
+def get_book_thumbnails(book_id, thumbnails=None):
+    return list(filter(lambda t: t.book_id == book_id, thumbnails)) if book_id > -1 and thumbnails else list()
+
+
+@jinjia.app_template_filter('get_book_thumbnail_srcset')
+def get_book_thumbnail_srcset(thumbnails):
+    srcset = list()
+    for thumbnail in thumbnails:
+        timestamp = int(thumbnail.generated_at.timestamp() * 1000)
+        cache_id = str(thumbnail.uuid) + '_' + str(timestamp)
+        url = url_for('web.get_cached_cover_thumbnail', cache_id=cache_id)
+        srcset.append(url + ' ' + str(thumbnail.resolution) + 'x')
+    return ', '.join(srcset)
diff --git a/cps/schedule.py b/cps/schedule.py
index f349a231..7ee43410 100644
--- a/cps/schedule.py
+++ b/cps/schedule.py
@@ -20,17 +20,17 @@ from __future__ import division, print_function, unicode_literals
 
 from .services.background_scheduler import BackgroundScheduler
 from .tasks.database import TaskReconnectDatabase
-from .tasks.thumbnail import TaskCleanupCoverThumbnailCache, TaskGenerateCoverThumbnails
+from .tasks.thumbnail import TaskSyncCoverThumbnailCache, TaskGenerateCoverThumbnails
 
 
 def register_jobs():
     scheduler = BackgroundScheduler()
 
     # Generate 100 book cover thumbnails every 5 minutes
-    scheduler.add_task(user=None, task=lambda: TaskGenerateCoverThumbnails(limit=100), trigger='interval', minutes=5)
+    scheduler.add_task(user=None, task=lambda: TaskGenerateCoverThumbnails(limit=100), trigger='cron', minute='*/5')
 
-    # Cleanup book cover cache every day at 4am
-    scheduler.add_task(user=None, task=lambda: TaskCleanupCoverThumbnailCache(), trigger='cron', hour=4)
+    # Cleanup book cover cache every 6 hours
+    scheduler.add_task(user=None, task=lambda: TaskSyncCoverThumbnailCache(), trigger='cron', minute='15', hour='*/6')
 
     # Reconnect metadata.db every 4 hours
-    scheduler.add_task(user=None, task=lambda: TaskReconnectDatabase(), trigger='interval', hours=4)
+    scheduler.add_task(user=None, task=lambda: TaskReconnectDatabase(), trigger='cron', minute='5', hour='*/4')
diff --git a/cps/tasks/thumbnail.py b/cps/tasks/thumbnail.py
index b541bc70..e9df170e 100644
--- a/cps/tasks/thumbnail.py
+++ b/cps/tasks/thumbnail.py
@@ -59,6 +59,10 @@ class TaskGenerateCoverThumbnails(CalibreTask):
             books_without_thumbnails = self.get_books_without_thumbnails(thumbnail_book_ids)
 
             count = len(books_without_thumbnails)
+            if count == 0:
+                # Do not display this task on the frontend if there are no covers to update
+                self.self_cleanup = True
+
             for i, book in enumerate(books_without_thumbnails):
                 for resolution in self.resolutions:
                     expired_thumbnail = self.get_expired_thumbnail_for_book_and_resolution(
@@ -71,6 +75,7 @@ class TaskGenerateCoverThumbnails(CalibreTask):
                     else:
                         self.create_book_thumbnail(book, resolution)
 
+                self.message(u'Generating cover thumbnail {0} of {1}'.format(i, count))
                 self.progress = (1.0 / count) * i
 
         self._handleSuccess()
@@ -181,12 +186,12 @@ class TaskGenerateCoverThumbnails(CalibreTask):
 
     @property
     def name(self):
-        return "GenerateCoverThumbnails"
+        return "ThumbnailsGenerate"
 
 
-class TaskCleanupCoverThumbnailCache(CalibreTask):
-    def __init__(self, task_message=u'Cleaning up cover thumbnail cache'):
-        super(TaskCleanupCoverThumbnailCache, self).__init__(task_message)
+class TaskSyncCoverThumbnailCache(CalibreTask):
+    def __init__(self, task_message=u'Syncing cover thumbnail cache'):
+        super(TaskSyncCoverThumbnailCache, self).__init__(task_message)
         self.log = logger.create()
         self.app_db_session = ub.get_new_session_instance()
         self.calibre_db = db.CalibreDB(expire_on_commit=False)
@@ -199,14 +204,23 @@ class TaskCleanupCoverThumbnailCache(CalibreTask):
         # This case will happen if a user deletes the cache dir or cached files
         if self.app_db_session:
             self.expire_missing_thumbnails(cached_thumbnail_files)
-            self.progress = 0.33
+            self.progress = 0.25
 
         # Delete thumbnails in the database if the book has been removed
         # This case will happen if a book is removed in Calibre and the metadata.db file is updated in the filesystem
         if self.app_db_session and self.calibre_db:
             book_ids = self.get_book_ids()
             self.delete_thumbnails_for_missing_books(book_ids)
-            self.progress = 0.66
+            self.progress = 0.50
+
+        # Expire thumbnails in the database if their corresponding book has been updated since they were generated
+        # This case will happen if the book was updated externally
+        if self.app_db_session and self.cache:
+            books = self.get_books_updated_in_the_last_day()
+            book_ids = list(map(lambda b: b.id, books))
+            thumbnails = self.get_thumbnails_for_updated_books(book_ids)
+            self.expire_thumbnails_for_updated_book(books, thumbnails)
+            self.progress = 0.75
 
         # Delete extraneous cached thumbnail files
         # This case will happen if a book was deleted and the thumbnail OR the metadata.db file was changed externally
@@ -261,9 +275,40 @@ class TaskCleanupCoverThumbnailCache(CalibreTask):
         for file in extraneous_files:
             self.cache.delete_cache_file(file, fs.CACHE_TYPE_THUMBNAILS)
 
+    def get_books_updated_in_the_last_day(self):
+        return self.calibre_db.session\
+            .query(db.Books)\
+            .filter(db.Books.has_cover == 1)\
+            .filter(db.Books.last_modified > datetime.utcnow() - timedelta(days=1, hours=1))\
+            .all()
+
+    def get_thumbnails_for_updated_books(self, book_ids):
+        return self.app_db_session\
+            .query(ub.Thumbnail)\
+            .filter(ub.Thumbnail.book_id.in_(book_ids))\
+            .all()
+
+    def expire_thumbnails_for_updated_book(self, books, thumbnails):
+        thumbnail_ids = list()
+        for book in books:
+            for thumbnail in thumbnails:
+                if thumbnail.book_id == book.id and thumbnail.generated_at < book.last_modified:
+                    thumbnail_ids.append(thumbnail.id)
+
+        try:
+            self.app_db_session\
+                .query(ub.Thumbnail)\
+                .filter(ub.Thumbnail.id.in_(thumbnail_ids)) \
+                .update({"expiration": datetime.utcnow()}, synchronize_session=False)
+            self.app_db_session.commit()
+        except Exception as ex:
+            self.log.info(u'Error expiring thumbnails for updated books: ' + str(ex))
+            self._handleError(u'Error expiring thumbnails for updated books: ' + str(ex))
+            self.app_db_session.rollback()
+
     @property
     def name(self):
-        return "CleanupCoverThumbnailCache"
+        return "ThumbnailsSync"
 
 
 class TaskClearCoverThumbnailCache(CalibreTask):
@@ -318,4 +363,4 @@ class TaskClearCoverThumbnailCache(CalibreTask):
 
     @property
     def name(self):
-        return "ClearCoverThumbnailCache"
+        return "ThumbnailsClear"
diff --git a/cps/templates/author.html b/cps/templates/author.html
index 3cf3fb4b..e5acdd2f 100644
--- a/cps/templates/author.html
+++ b/cps/templates/author.html
@@ -36,7 +36,7 @@
     <div id="books" class="col-sm-3 col-lg-2 col-xs-6 book">
       <div class="cover">
         <a href="{{ url_for('web.show_book', book_id=entry.id) }}">
-            {{ book_cover_image(entry, entry.title) }}
+            {{ book_cover_image(entry, entry.id|get_book_thumbnails(thumbnails)) }}
         </a>
       </div>
       <div class="meta">
diff --git a/cps/templates/book_cover.html b/cps/templates/book_cover.html
index 3f0ed154..c5281797 100644
--- a/cps/templates/book_cover.html
+++ b/cps/templates/book_cover.html
@@ -1,8 +1,13 @@
-{% macro book_cover_image(book, book_title) -%}
-    <img
-        srcset="{{ url_for('web.get_cached_cover', cache_id=book|book_cover_cache_id(1)) }} 1x,
-                {{ url_for('web.get_cached_cover', cache_id=book|book_cover_cache_id(2)) }} 2x"
-        src="{{ url_for('web.get_cached_cover', cache_id=book|book_cover_cache_id) }}"
-        alt="{{ book_title }}"
-    />
+{% macro book_cover_image(book, thumbnails) -%}
+    {%- set book_title = book.title if book.title else book.name -%}
+    {% set srcset = thumbnails|get_book_thumbnail_srcset if thumbnails|length else '' %}
+    {%- if srcset|length -%}
+        <img
+            srcset="{{ srcset }}"
+            src="{{ url_for('web.get_cached_cover', cache_id=book|book_cover_cache_id) }}"
+            alt="{{ book_title }}"
+        />
+    {%- else -%}
+        <img src="{{ url_for('web.get_cached_cover', cache_id=book|book_cover_cache_id) }}" alt="{{ book_title }}" />
+    {%- endif -%}
 {%- endmacro %}
diff --git a/cps/templates/book_edit.html b/cps/templates/book_edit.html
index 369b8d05..c538d5ca 100644
--- a/cps/templates/book_edit.html
+++ b/cps/templates/book_edit.html
@@ -4,7 +4,7 @@
 {% if book %}
   <div class="col-sm-3 col-lg-3 col-xs-12">
     <div class="cover">
-        {{ book_cover_image(book, book.title) }}
+        {{ book_cover_image(book, book.id|get_book_thumbnails(thumbnails)) }}
     </div>
 {% if g.user.role_delete_books() %}
     <div class="text-center">
diff --git a/cps/templates/detail.html b/cps/templates/detail.html
index cdf6ab2b..671186c7 100644
--- a/cps/templates/detail.html
+++ b/cps/templates/detail.html
@@ -4,7 +4,7 @@
   <div class="row">
     <div class="col-sm-3 col-lg-3 col-xs-5">
       <div class="cover">
-          {{ book_cover_image(entry, entry.title) }}
+          {{ book_cover_image(entry, entry.id|get_book_thumbnails(thumbnails)) }}
       </div>
     </div>
     <div class="col-sm-9 col-lg-9 book-meta">
diff --git a/cps/templates/discover.html b/cps/templates/discover.html
index 5d4666f6..c5c12db2 100644
--- a/cps/templates/discover.html
+++ b/cps/templates/discover.html
@@ -9,7 +9,7 @@
       <div class="cover">
         {% if entry.has_cover is defined %}
           <a href="{{ url_for('web.show_book', book_id=entry.id) }}" data-toggle="modal" data-target="#bookDetailsModal" data-remote="false">
-              {{ book_cover_image(entry, entry.title) }}
+              {{ book_cover_image(entry, entry.id|get_book_thumbnails(thumbnails)) }}
           </a>
         {% endif %}
       </div>
diff --git a/cps/templates/grid.html b/cps/templates/grid.html
index 67594b4e..0f669d51 100644
--- a/cps/templates/grid.html
+++ b/cps/templates/grid.html
@@ -29,7 +29,7 @@
               <div class="col-sm-3 col-lg-2 col-xs-6 book sortable" {% if entry[0].sort %}data-name="{{entry[0].series[0].name}}"{% endif %} data-id="{% if entry[0].series[0].name %}{{entry[0].series[0].name}}{% endif %}">
                   <div class="cover">
                       <a href="{{url_for('web.books_list', data=data, sort_param='new', book_id=entry[0].series[0].id )}}">
-                          {{ book_cover_image(entry[0], entry[0].name) }}
+                          {{ book_cover_image(entry[0], entry[0].id|get_book_thumbnails(thumbnails)) }}
                           <span class="badge">{{entry.count}}</span>
                       </a>
                   </div>
diff --git a/cps/templates/index.html b/cps/templates/index.html
index 531a535c..2be15ba7 100644
--- a/cps/templates/index.html
+++ b/cps/templates/index.html
@@ -9,7 +9,7 @@
     <div class="col-sm-3 col-lg-2 col-xs-6 book" id="books_rand">
       <div class="cover">
           <a href="{{ url_for('web.show_book', book_id=entry.id) }}" data-toggle="modal" data-target="#bookDetailsModal" data-remote="false">
-              {{ book_cover_image(entry, entry.title) }}
+              {{ book_cover_image(entry, entry.id|get_book_thumbnails(thumbnails)) }}
           </a>
       </div>
       <div class="meta">
@@ -83,7 +83,7 @@
     <div class="col-sm-3 col-lg-2 col-xs-6 book" id="books">
       <div class="cover">
           <a href="{{ url_for('web.show_book', book_id=entry.id) }}" data-toggle="modal" data-target="#bookDetailsModal" data-remote="false">
-              {{ book_cover_image(entry, entry.title) }}
+              {{ book_cover_image(entry, entry.id|get_book_thumbnails(thumbnails)) }}
           </a>
       </div>
       <div class="meta">
diff --git a/cps/templates/search.html b/cps/templates/search.html
index 8e0cf668..a5871afb 100644
--- a/cps/templates/search.html
+++ b/cps/templates/search.html
@@ -44,7 +44,7 @@
       <div class="cover">
         {% if entry.has_cover is defined %}
            <a href="{{ url_for('web.show_book', book_id=entry.id) }}" data-toggle="modal" data-target="#bookDetailsModal" data-remote="false">
-               {{ book_cover_image(entry, entry.title) }}
+               {{ book_cover_image(entry, entry.id|get_book_thumbnails(thumbnails)) }}
           </a>
         {% endif %}
       </div>
diff --git a/cps/templates/shelf.html b/cps/templates/shelf.html
index bebc0b1f..cb55c50c 100644
--- a/cps/templates/shelf.html
+++ b/cps/templates/shelf.html
@@ -31,7 +31,7 @@
     <div class="col-sm-3 col-lg-2 col-xs-6 book">
       <div class="cover">
             <a href="{{ url_for('web.show_book', book_id=entry.id) }}" data-toggle="modal" data-target="#bookDetailsModal" data-remote="false">
-                {{ book_cover_image(entry, entry.title) }}
+                {{ book_cover_image(entry, entry.id|get_book_thumbnails(thumbnails)) }}
             </a>
       </div>
       <div class="meta">
diff --git a/cps/web.py b/cps/web.py
index 16c14fcf..c400b96e 100644
--- a/cps/web.py
+++ b/cps/web.py
@@ -49,9 +49,10 @@ from . import constants, logger, isoLanguages, services
 from . import babel, db, ub, config, get_locale, app
 from . import calibre_db, shelf
 from .gdriveutils import getFileFromEbooksFolder, do_gdrive_download
-from .helper import check_valid_domain, render_task_status, \
-    get_cc_columns, get_book_cover, get_cached_book_cover, get_download_link, send_mail, generate_random_password, \
-    send_registration_mail, check_send_to_kindle, check_read_formats, tags_filters, reset_password
+from .helper import check_valid_domain, render_task_status, get_cc_columns, get_book_cover, get_cached_book_cover, \
+    get_cached_book_cover_thumbnail, get_thumbnails_for_books, get_thumbnails_for_book_series, get_download_link, \
+    send_mail, generate_random_password, send_registration_mail, check_send_to_kindle, check_read_formats, \
+    tags_filters, reset_password
 from .pagination import Pagination
 from .redirect import redirect_back
 from .usermanagement import login_required_if_no_ano
@@ -386,16 +387,18 @@ def render_books_list(data, sort, book_id, page):
                                                                     db.Books,
                                                                     db.Books.ratings.any(db.Ratings.rating > 9),
                                                                     order)
+            thumbnails = get_thumbnails_for_books(entries + random)
             return render_title_template('index.html', random=random, entries=entries, pagination=pagination,
-                                         id=book_id, title=_(u"Top Rated Books"), page="rated")
+                                         id=book_id, title=_(u"Top Rated Books"), page="rated", thumbnails=thumbnails)
         else:
             abort(404)
     elif data == "discover":
         if current_user.check_visibility(constants.SIDEBAR_RANDOM):
             entries, __, pagination = calibre_db.fill_indexpage(page, 0, db.Books, True, [func.randomblob(2)])
             pagination = Pagination(1, config.config_books_per_page, config.config_books_per_page)
+            thumbnails = get_thumbnails_for_books(entries)
             return render_title_template('discover.html', entries=entries, pagination=pagination, id=book_id,
-                                         title=_(u"Discover (Random Books)"), page="discover")
+                                         title=_(u"Discover (Random Books)"), page="discover", thumbnails=thumbnails)
         else:
             abort(404)
     elif data == "unread":
@@ -433,8 +436,9 @@ def render_books_list(data, sort, book_id, page):
     else:
         website = data or "newest"
         entries, random, pagination = calibre_db.fill_indexpage(page, 0, db.Books, True, order)
+        thumbnails = get_thumbnails_for_books(entries + random)
         return render_title_template('index.html', random=random, entries=entries, pagination=pagination,
-                                     title=_(u"Books"), page=website)
+                                     title=_(u"Books"), page=website, thumbnails=thumbnails)
 
 
 def render_hot_books(page):
@@ -458,8 +462,9 @@ def render_hot_books(page):
                 ub.delete_download(book.Downloads.book_id)
         numBooks = entries.__len__()
         pagination = Pagination(page, config.config_books_per_page, numBooks)
+        thumbnails = get_thumbnails_for_books(entries + random)
         return render_title_template('index.html', random=random, entries=entries, pagination=pagination,
-                                     title=_(u"Hot Books (Most Downloaded)"), page="hot")
+                                     title=_(u"Hot Books (Most Downloaded)"), page="hot", thumbnails=thumbnails)
     else:
         abort(404)
 
@@ -490,12 +495,14 @@ def render_downloaded_books(page, order):
                              .filter(db.Books.id == book.id).first():
                 ub.delete_download(book.id)
 
+        thumbnails = get_thumbnails_for_books(entries + random)
         return render_title_template('index.html',
                                      random=random,
                                      entries=entries,
                                      pagination=pagination,
                                      title=_(u"Downloaded books by %(user)s",user=current_user.nickname),
-                                     page="download")
+                                     page="download",
+                                     thumbnails=thumbnails)
     else:
         abort(404)
 
@@ -521,9 +528,10 @@ def render_author_books(page, author_id, order):
         author_info = services.goodreads_support.get_author_info(author_name)
         other_books = services.goodreads_support.get_other_books(author_info, entries)
 
+    thumbnails = get_thumbnails_for_books(entries)
     return render_title_template('author.html', entries=entries, pagination=pagination, id=author_id,
                                  title=_(u"Author: %(name)s", name=author_name), author=author_info,
-                                 other_books=other_books, page="author")
+                                 other_books=other_books, page="author", thumbnails=thumbnails)
 
 
 def render_publisher_books(page, book_id, order):
@@ -535,8 +543,10 @@ def render_publisher_books(page, book_id, order):
                                                                 [db.Series.name, order[0], db.Books.series_index],
                                                                 db.books_series_link,
                                                                 db.Series)
+        thumbnails = get_thumbnails_for_books(entries + random)
         return render_title_template('index.html', random=random, entries=entries, pagination=pagination, id=book_id,
-                                     title=_(u"Publisher: %(name)s", name=publisher.name), page="publisher")
+                                     title=_(u"Publisher: %(name)s", name=publisher.name), page="publisher",
+                                     thumbnails=thumbnails)
     else:
         abort(404)
 
@@ -548,8 +558,10 @@ def render_series_books(page, book_id, order):
                                                                 db.Books,
                                                                 db.Books.series.any(db.Series.id == book_id),
                                                                 [order[0]])
+        thumbnails = get_thumbnails_for_books(entries + random)
         return render_title_template('index.html', random=random, pagination=pagination, entries=entries, id=book_id,
-                                     title=_(u"Series: %(serie)s", serie=name.name), page="series")
+                                     title=_(u"Series: %(serie)s", serie=name.name), page="series",
+                                     thumbnails=thumbnails)
     else:
         abort(404)
 
@@ -561,8 +573,10 @@ def render_ratings_books(page, book_id, order):
                                                             db.Books.ratings.any(db.Ratings.id == book_id),
                                                             [order[0]])
     if name and name.rating <= 10:
+        thumbnails = get_thumbnails_for_books(entries + random)
         return render_title_template('index.html', random=random, pagination=pagination, entries=entries, id=book_id,
-                                     title=_(u"Rating: %(rating)s stars", rating=int(name.rating / 2)), page="ratings")
+                                     title=_(u"Rating: %(rating)s stars", rating=int(name.rating / 2)), page="ratings",
+                                     thumbnails=thumbnails)
     else:
         abort(404)
 
@@ -574,8 +588,10 @@ def render_formats_books(page, book_id, order):
                                                                 db.Books,
                                                                 db.Books.data.any(db.Data.format == book_id.upper()),
                                                                 [order[0]])
+        thumbnails = get_thumbnails_for_books(entries + random)
         return render_title_template('index.html', random=random, pagination=pagination, entries=entries, id=book_id,
-                                     title=_(u"File format: %(format)s", format=name.format), page="formats")
+                                     title=_(u"File format: %(format)s", format=name.format), page="formats",
+                                     thumbnails=thumbnails)
     else:
         abort(404)
 
@@ -588,8 +604,10 @@ def render_category_books(page, book_id, order):
                                                                 db.Books.tags.any(db.Tags.id == book_id),
                                                                 [order[0], db.Series.name, db.Books.series_index],
                                                                 db.books_series_link, db.Series)
+        thumbnails = get_thumbnails_for_books(entries + random)
         return render_title_template('index.html', random=random, entries=entries, pagination=pagination, id=book_id,
-                                     title=_(u"Category: %(name)s", name=name.name), page="category")
+                                     title=_(u"Category: %(name)s", name=name.name), page="category",
+                                     thumbnails=thumbnails)
     else:
         abort(404)
 
@@ -607,8 +625,9 @@ def render_language_books(page, name, order):
                                                             db.Books,
                                                             db.Books.languages.any(db.Languages.lang_code == name),
                                                             [order[0]])
+    thumbnails = get_thumbnails_for_books(entries + random)
     return render_title_template('index.html', random=random, entries=entries, pagination=pagination, id=name,
-                                 title=_(u"Language: %(name)s", name=lang_name), page="language")
+                                 title=_(u"Language: %(name)s", name=lang_name), page="language", thumbnails=thumbnails)
 
 
 def render_read_books(page, are_read, as_xml=False, order=None):
@@ -652,8 +671,10 @@ def render_read_books(page, are_read, as_xml=False, order=None):
         else:
             name = _(u'Unread Books') + ' (' + str(pagination.total_count) + ')'
             pagename = "unread"
+
+        thumbnails = get_thumbnails_for_books(entries + random)
         return render_title_template('index.html', random=random, entries=entries, pagination=pagination,
-                                     title=name, page=pagename)
+                                     title=name, page=pagename, thumbnails=thumbnails)
 
 
 def render_archived_books(page, order):
@@ -676,8 +697,9 @@ def render_archived_books(page, order):
 
     name = _(u'Archived Books') + ' (' + str(len(archived_book_ids)) + ')'
     pagename = "archived"
+    thumbnails = get_thumbnails_for_books(entries + random)
     return render_title_template('index.html', random=random, entries=entries, pagination=pagination,
-                                 title=name, page=pagename)
+                                 title=name, page=pagename, thumbnails=thumbnails)
 
 
 def render_prepare_search_form(cc):
@@ -710,6 +732,7 @@ def render_prepare_search_form(cc):
 
 def render_search_results(term, offset=None, order=None, limit=None):
     entries, result_count, pagination = calibre_db.get_search_results(term, offset, order, limit)
+    thumbnails = get_thumbnails_for_books(entries)
     return render_title_template('search.html',
                                  searchterm=term,
                                  pagination=pagination,
@@ -718,7 +741,8 @@ def render_search_results(term, offset=None, order=None, limit=None):
                                  entries=entries,
                                  result_count=result_count,
                                  title=_(u"Search"),
-                                 page="search")
+                                 page="search",
+                                 thumbnails=thumbnails)
 
 
 # ################################### View Books list ##################################################################
@@ -748,6 +772,7 @@ def books_table():
     return render_title_template('book_table.html', title=_(u"Books List"), page="book_table",
                                  visiblility=visibility)
 
+
 @web.route("/ajax/listbooks")
 @login_required
 def list_books():
@@ -780,6 +805,7 @@ def list_books():
     response.headers["Content-Type"] = "application/json; charset=utf-8"
     return response
 
+
 @web.route("/ajax/table_settings", methods=['POST'])
 @login_required
 def update_table_settings():
@@ -834,6 +860,7 @@ def publisher_list():
         charlist = calibre_db.session.query(func.upper(func.substr(db.Publishers.name, 1, 1)).label('char')) \
             .join(db.books_publishers_link).join(db.Books).filter(calibre_db.common_filters()) \
             .group_by(func.upper(func.substr(db.Publishers.name, 1, 1))).all()
+
         return render_title_template('list.html', entries=entries, folder='web.books_list', charlist=charlist,
                                      title=_(u"Publishers"), page="publisherlist", data="publisher")
     else:
@@ -865,8 +892,10 @@ def series_list():
                 .join(db.books_series_link).join(db.Books).filter(calibre_db.common_filters()) \
                 .group_by(func.upper(func.substr(db.Series.sort, 1, 1))).all()
 
+            thumbnails = get_thumbnails_for_book_series(entries)
             return render_title_template('grid.html', entries=entries, folder='web.books_list', charlist=charlist,
-                                         title=_(u"Series"), page="serieslist", data="series", bodyClass="grid-view")
+                                         title=_(u"Series"), page="serieslist", data="series", bodyClass="grid-view",
+                                         thumbnails=thumbnails)
     else:
         abort(404)
 
@@ -1150,13 +1179,16 @@ def render_adv_search_results(term, offset=None, order=None, limit=None):
     else:
         offset = 0
         limit_all = result_count
+
+    thumbnails = get_thumbnails_for_books(entries)
     return render_title_template('search.html',
                                  adv_searchterm=searchterm,
                                  pagination=pagination,
                                  entries=q[offset:limit_all],
                                  result_count=result_count,
-                                 title=_(u"Advanced Search"), page="advsearch")
-
+                                 title=_(u"Advanced Search"),
+                                 page="advsearch",
+                                 thumbnails=thumbnails)
 
 
 @web.route("/advsearch", methods=['GET'])
@@ -1171,10 +1203,9 @@ def advanced_search_form():
 
 
 @web.route("/cover/<int:book_id>")
-@web.route("/cover/<int:book_id>/<int:resolution>")
 @login_required_if_no_ano
-def get_cover(book_id, resolution=1):
-    return get_book_cover(book_id, resolution)
+def get_cover(book_id):
+    return get_book_cover(book_id)
 
 
 @web.route("/cached-cover/<string:cache_id>")
@@ -1183,6 +1214,12 @@ def get_cached_cover(cache_id):
     return get_cached_book_cover(cache_id)
 
 
+@web.route("/cached-cover-thumbnail/<string:cache_id>")
+@login_required_if_no_ano
+def get_cached_cover_thumbnail(cache_id):
+    return get_cached_book_cover_thumbnail(cache_id)
+
+
 @web.route("/robots.txt")
 def get_robots():
     return send_from_directory(constants.STATIC_DIR, "robots.txt")
@@ -1591,6 +1628,7 @@ def show_book(book_id):
             if media_format.format.lower() in constants.EXTENSIONS_AUDIO:
                 audioentries.append(media_format.format.lower())
 
+        thumbnails = get_thumbnails_for_books([entries])
         return render_title_template('detail.html',
                                      entry=entries,
                                      audioentries=audioentries,
@@ -1602,7 +1640,8 @@ def show_book(book_id):
                                      is_archived=is_archived,
                                      kindle_list=kindle_list,
                                      reader_list=reader_list,
-                                     page="book")
+                                     page="book",
+                                     thumbnails=thumbnails)
     else:
         log.debug(u"Error opening eBook. File does not exist or file is not accessible")
         flash(_(u"Error opening eBook. File does not exist or file is not accessible"), category="error")