$re = '/(-scaled|[_-]\d+x\d+)|@[2-6]\x(?=\.[a-z]{3,4}$)|\.[a-z]{3,4}.webp/im';
$str = 'skip-IMG_7484-scaled.jpg
skip-IMG_7484.jpeg.webp
skip-IMG_7484.jpg.webp
skip-filename_500x383dddd.jpeg
skip-filename_500x383.jpeg
skip-filename-500x383.jpeg
skip-filename-500x383.jpg
skip-filename-500x383@2xddddd.jpg
skip-filename-500x383@2x.jpg
skip-filename-100x100@2x.jpg
skip-filename-1000x1000@3x.jpg
skip-filename-40x40@4x.jpg
keep-filename@2x copy.jpg
keep-filename@2x.jpg
keep-filename@3x.jpg
keep-filename@4x.jpg
keep-IMG_7484-normal-webp.webp
keep-IMG_7484-not-dot-jpg.webp
keep-IMG_7484.jpg
keep-f5229.jpg
keep-f5229as\'ad"an.jpg';
preg_match_all($re, $str, $matches, PREG_SET_ORDER, 0);
// Print the entire match result
var_dump($matches);
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for PHP, please visit: http://php.net/manual/en/ref.pcre.php