WordPress/wp-admin/js/media-gallery.js

jQuery(function(a){a("body").bind("click.wp-gallery",function(d){var c=a(d.target),f,b;if(c.hasClass("wp-set-header")){(window.dialogArguments||opener||parent||top).location.href=c.data("location");d.preventDefault()}else{if(c.hasClass("wp-set-background")){f=c.data("attachment-id");b=a('input[name="attachments['+f+'][image-size]"]:checked').val();jQuery.post(ajaxurl,{action:"set-background-image",attachment_id:f,size:b},function(){var e=window.dialogArguments||opener||parent||top;e.tb_remove();e.location.reload()});d.preventDefault()}}})});