getjpgexample.php

<?php

$Directory = new RecursiveDirectoryIterator('path/to/project/');
$Iterator = new RecursiveIteratorIterator($Directory);
$array = new RegexIterator($Iterator, '/^.+\.jpg$/i', RecursiveRegexIterator::GET_MATCH);

    
foreach($array as $arr){
    if(preg_match('/.*[0-9].(?:jpg)/',$arr) || strpos($arr,'coverleft') !== false || strpos($arr,'coverright') !== false){
        echo $arr . ' Was Found ' . PHP_EOL;
    }
    else{
        echo $arr . ' Not Found ' . PHP_EOL;
    }
}

?>