diff --git src/wp-includes/js/tinymce/plugins/wpeditimage/plugin.js src/wp-includes/js/tinymce/plugins/wpeditimage/plugin.js
index f3e66e6..8db5d37 100644
--- src/wp-includes/js/tinymce/plugins/wpeditimage/plugin.js
+++ src/wp-includes/js/tinymce/plugins/wpeditimage/plugin.js
@@ -498,7 +498,7 @@ tinymce.PluginManager.add( 'wpeditimage', function( editor ) {
         var parent,
 			node = event.target;
 
-		if ( node.nodeName === 'IMG' && ( parent = editor.dom.getParent( node, '.wp-caption' ) ) ) {
+		if ( node.nodeName === 'IMG' && ( parent = editor.dom.getParent( node, '.wp-caption' ) && event.width > 0 ) ) {
 			editor.dom.setStyle( parent, 'width', 10 + event.width + 'px' );
 		}
     });