Index: src/wp-admin/css/widgets.css
===================================================================
--- src/wp-admin/css/widgets.css	(revision 42444)
+++ src/wp-admin/css/widgets.css	(working copy)
@@ -177,9 +177,7 @@
 	cursor: pointer;
 }
 
-.media-widget-preview.media_image,
-.media-widget-preview.media_audio,
-.attachment-media-view {
+.media-widget-preview .placeholder {
 	background: #f1f1f1;
 }
 
@@ -190,7 +188,7 @@
 	background: transparent;
 }
 
-.media-widget-gallery-preview .gallery-item .gallery-icon { 
+.media-widget-gallery-preview .gallery-item .gallery-icon {
 	margin: 4.5%;
 }