Add [is[image]] filter operator

core/modules/filters/is/image.js

@@ -0,0 +1,43 @@
+/*\
+title: $:/core/modules/filters/is/image.js
+type: application/javascript
+module-type: isfilteroperator
+
+Filter function for [is[image]]
+
+\*/
+(function(){
+
+/*jslint node: true, browser: true */
+/*global $tw: false */
+"use strict";
+
+/*
+Export our filter function
+*/
+exports.image = function(source,prefix,options) {
+	var results = [];
+	// Function to check a tiddler
+	function checkTiddler(title) {
+		var match = options.wiki.isImageTiddler(title);
+		if(prefix === "!") {
+			match = !match;
+		}
+		if(match) {
+			results.push(title);
+		}
+	};
+	// Iterate through the source tiddlers
+	if($tw.utils.isArray(source)) {
+		$tw.utils.each(source,function(title) {
+			checkTiddler(title);
+		});
+	} else {
+		$tw.utils.each(source,function(element,title) {
+			checkTiddler(title);
+		});
+	}
+	return results;
+};
+
+})();

core/modules/wiki.js

@@ -196,6 +196,16 @@ exports.isShadowTiddler = function(title) {
 	return $tw.utils.hop(this.shadowTiddlers,title);
 };
 
+exports.isImageTiddler = function(title) {
+	var tiddler = this.getTiddler(title);
+	if(tiddler) {		
+		var contentTypeInfo = $tw.config.contentTypeInfo[tiddler.fields.type || "text/vnd.tiddlywiki"];
+		return !!contentTypeInfo && contentTypeInfo.flags.indexOf("image") !== -1;
+	} else {
+		return null;
+	}
+};
+
 exports.addTiddler = function(tiddler) {
 	// Check if we're passed a fields hashmap instead of a tiddler
 	if(!(tiddler instanceof $tw.Tiddler)) {