Fairly simple using jQuery and global $typenow ex: add_action(‘admin_print_scripts-post.php’, ‘my_publish_admin_hook’); add_action(‘admin_print_scripts-post-new.php’, ‘my_publish_admin_hook’); function my_publish_admin_hook(){ global $typenow; if (in_array($typenow, array(‘post’,’page’,’mm_photo ‘))){ ?> <script language=”javascript” type=”text/javascript”> jQuery(document).ready(function() { jQuery(‘#post’).submit(function() { if (jQuery(“#set-post-thumbnail”).find(‘img’).size() > 0) { jQuery(‘#ajax-loading’).hide(); jQuery(‘#publish’).removeClass(‘button-primary-disabled’); return true; }else{ alert(“please set a featured image!!!”); jQuery(‘#ajax-loading’).hide(); jQuery(‘#publish’).removeClass(‘button-primary-disabled’); return false; } return false; }); }); </script> <?php } … Read more