Fix image preview not resized correctly in the mediatag dialog

www/pad/app-pad.less

@@ -59,9 +59,6 @@ body.cp-app-pad {
                 display: flex;
                 border-style: solid;
                 border-color: black;
-                &> * {
-                    flex-shrink: 0;
-                }
             }
         }
     }

www/pad/mediatag-plugin-dialog.js

@@ -118,7 +118,7 @@ CKEDITOR.dialog.add('mediatag', function (editor) {
                 update();
             });
 
-            setTimeout(center);
+            setTimeout(update);
         },
         onOk: function() {
             var dialog = this;