Delete image code-PHP source code

Delete the image code in the image code project. I hope you can give some security suggestions.

If (isset ($ _ SERVER ['http _ X_REQUESTED_WITH ']) & strtolower ($ _ SERVER ['http _ X_REQUESTED_WITH']) = 'xmlhttprequest ') {$ url = $ _ GET ['json']; $ url = $ _ SERVER ['document _ root']. urldecode ($ url ['picurl']); $ pictype = array ("gif", "jpg", "jpeg", "png", "bmp "); if (file_exists ($ url) {$ infos = pathinfo ($ url); if (in_array ($ infos ['extension'], $ pictype) & strpos ($ url, "uploadfile") {if (unlink ($ url) {echo json_encode (array ( "Status" => "1", "info" => L ('deleted successfully! ');} Else {echo json_encode (array ("status" => "2", "info" => L ("deletion failed, please check the permission! ") ;}} Else {echo json_encode (array (" status "=>" 2 "," info "=> L (" deletion failed, please check the permission! ") ;}} Else {echo json_encode (array (" status "=>" 0 ", "info" => L ("The file does not exist or has been deleted ")));}}