diff --git a/core/config/editor-type-mappings/image-gif.tid b/core/config/editor-type-mappings/image-gif.tid
new file mode 100644
index 000000000..7f66c8434
--- /dev/null
+++ b/core/config/editor-type-mappings/image-gif.tid
@@ -0,0 +1,3 @@
+title: $:/config/EditorTypeMappings/image/gif
+
+bitmap
\ No newline at end of file
diff --git a/core/config/editor-type-mappings/image-jpeg.tid b/core/config/editor-type-mappings/image-jpeg.tid
new file mode 100644
index 000000000..02a0943ca
--- /dev/null
+++ b/core/config/editor-type-mappings/image-jpeg.tid
@@ -0,0 +1,3 @@
+title: $:/config/EditorTypeMappings/image/jpeg
+
+bitmap
\ No newline at end of file
diff --git a/core/config/editor-type-mappings/image-jpg.tid b/core/config/editor-type-mappings/image-jpg.tid
new file mode 100644
index 000000000..d1eda17c7
--- /dev/null
+++ b/core/config/editor-type-mappings/image-jpg.tid
@@ -0,0 +1,3 @@
+title: $:/config/EditorTypeMappings/image/jpg
+
+bitmap
\ No newline at end of file
diff --git a/core/config/editor-type-mappings/image-png.tid b/core/config/editor-type-mappings/image-png.tid
new file mode 100644
index 000000000..4c4f613cd
--- /dev/null
+++ b/core/config/editor-type-mappings/image-png.tid
@@ -0,0 +1,3 @@
+title: $:/config/EditorTypeMappings/image/png
+
+bitmap
\ No newline at end of file
diff --git a/core/config/editor-type-mappings/image-x-icon.tid b/core/config/editor-type-mappings/image-x-icon.tid
new file mode 100644
index 000000000..d2b4d0d99
--- /dev/null
+++ b/core/config/editor-type-mappings/image-x-icon.tid
@@ -0,0 +1,3 @@
+title: $:/config/EditorTypeMappings/image/x-icon
+
+bitmap
\ No newline at end of file
diff --git a/core/config/editor-type-mappings/text-vnd-tiddlywiki.tid b/core/config/editor-type-mappings/text-vnd-tiddlywiki.tid
new file mode 100644
index 000000000..fee2a2a62
--- /dev/null
+++ b/core/config/editor-type-mappings/text-vnd-tiddlywiki.tid
@@ -0,0 +1,3 @@
+title: $:/config/EditorTypeMappings/text/vnd.tiddlywiki
+
+text
\ No newline at end of file
diff --git a/core/modules/widgets/edit.js b/core/modules/widgets/edit.js
index 26a0091d1..c5a7a4969 100644
--- a/core/modules/widgets/edit.js
+++ b/core/modules/widgets/edit.js
@@ -33,17 +33,8 @@ EditWidget.prototype.render = function(parent,nextSibling) {
 	this.renderChildren(parent,nextSibling);
 };
 
-// Mappings from content type to editor type
-// TODO: This information should be configurable/extensible
-var editorTypeMappings = {
-	"text/vnd.tiddlywiki": "text",
-	"image/svg+xml": "text",
-	"image/jpg": "bitmap",
-	"image/jpeg": "bitmap",
-	"image/gif": "bitmap",
-	"image/png": "bitmap",
-	"image/x-icon": "bitmap"
-};
+// Mappings from content type to editor type are stored in tiddlers with this prefix
+var EDITOR_MAPPING_PREFIX = "$:/config/EditorTypeMappings/";
 
 /*
 Compute the internal state of the widget
@@ -65,7 +56,7 @@ EditWidget.prototype.execute = function() {
 	}
 	type = type || "text/vnd.tiddlywiki";
 	// Choose the appropriate edit widget
-	var editorType = editorTypeMappings[type] || "text";
+	var editorType = this.wiki.getTiddlerText(EDITOR_MAPPING_PREFIX + type) || "text";
 	// Make the child widgets
 	this.makeChildWidgets([{
 		type: "edit-" + editorType,