diff --git a/plugins/mattermost/index.js b/plugins/mattermost/index.js
index 3d8eacea84d7b57b943ca486487d5b5e015f002b..66e0343ef475b931253f63df2f1d9922dd3f26d0 100644
--- a/plugins/mattermost/index.js
+++ b/plugins/mattermost/index.js
@@ -57,8 +57,15 @@ exports.initWebApp = function(options) {
     return '[' + text + '](' + url  + ')';
   };
 
-  var image = function(alt, url) {
-    return '![' + alt + '](' + url + ')';
+  var image = function(alt, url, width, height) {
+    var size = '';
+    if (width != undefined) {
+      size = ' =' + width + 'x';
+      if (height != undefined) {
+        size += height;
+      }
+    }
+    return '![' + alt + '](' + url + size + ')';
   };
 
   var getHook = function(check) {
diff --git a/plugins/tracker/sources/github/githubSource.js b/plugins/tracker/sources/github/githubSource.js
index dd286fbb458f43fe78c85cf10e550644b64e395e..8e627a8a8187fd5930a36a14b6cb6a99b7b3568f 100644
--- a/plugins/tracker/sources/github/githubSource.js
+++ b/plugins/tracker/sources/github/githubSource.js
@@ -60,7 +60,7 @@ GitHubTrackerSource.prototype.notifyItem = function(item) {
 
 GitHubTrackerSource.prototype.renderItem = function(item, linkCB, imageCB) {
   var url = item.repository.html_url,
-    avatar = imageCB('', item.repository.owner.avatar_url),
+    avatar = imageCB('', item.repository.owner.avatar_url, 50),
     project = item.repository.full_name,
     title = item.subject.title,
     type = '';