plugins: (image) support :size suffix

Some images URL (such as Twitter hosting site twimg.com) are suffixed
with :size where size can be small, medium or large.

js/plugins.js

@@ -257,7 +257,7 @@ plugins.factory('userPlugins', function() {
             var embed = false;
             // Check the get parameters as well, they might contain an image to load
             var segments = url.split(/[?&]/).forEach(function(param) {
-                if (param.match(/\.(png|gif|jpg|jpeg)$/i)) {
+                if (param.match(/\.(png|gif|jpg|jpeg)(:(small|medium|large))?$/i)) {
                     embed = true;
                 }
             });

test/unit/plugins.js

@@ -80,7 +80,9 @@ describe('filter', function() {
                 'https://4z2.de/gb-mobile-new.png',
                 'http://static.weechat.org/images/screenshots/relay/medium/glowing-bear.png',
                 'http://foo.bar/baz.php?img=trololo.png&dummy=yes',
-                'https://tro.lo.lo/images/rick.png?size=123x45'
+                'https://tro.lo.lo/images/rick.png?size=123x45',
+                'https://pbs.twimg.com/media/B66rbCuIMAAxiFF.jpg:large',
+                'https://pbs.twimg.com/media/B6OZuCYCEAEV8SA.jpg:medium'
             ],
             'image',
             plugins);