gistfile1.txt

/*------------------------------------------------------------
* Get Attachment ID from image src
* Author: http://stylishwp.com/ 
============================================================*/
if ( ! function_exists( 'swp_get_attachment_id_from_src' ) ) :
	function swp_get_attachment_id_from_src ( $image_src ) {
		global $wpdb;
		$id = $wpdb->get_var( $wpdb->prepare( "SELECT ID FROM {$wpdb->posts} WHERE guid = %s", $image_src) );
		return $id;
	}
endif;