Just accept all image types for profile pictures

This works as we render things on the browser into a canvas which will
be stored as png on the server

src/views/profile.html

@@ -21,7 +21,7 @@
         </div>
         <div ng-hide="avatarChange.useGravatar" class="preview-avatar">
           <img id="previewAvatar" width="128" height="128" class="copy" ng-click="avatarChange.showCustomAvatarSelector()"/>
-          <input type="file" id="avatarFileInput" style="display: none" accept="image/png"/>
+          <input type="file" id="avatarFileInput" style="display: none" accept="image/*"/>
         </div>
       </div>
       <div class="modal-footer">