Fixed styles for status ticks

Closes #754

app/less/desktop.less

@@ -998,6 +998,7 @@ a.footer_link.active:active {
         position: relative;
 
         .image-2x('../img/icons/Checks2.png', 16px, 10px);
+        background-size: 16px 10px;
         background-position: 0 0;
       }
     }
@@ -1011,6 +1012,7 @@ a.footer_link.active:active {
     &_unread {
       .icon-message-status-tick {
         .image-2x('../img/icons/Checks1.png', 16px, 10px);
+        background-size: 16px 10px;
         background-position: 0 0;
       }
     }