PHP script to read files from a DIR parsing through a filename regex to match extensions

read_files_from_dir.php

<?php

$files = array();
$folder = '../images';
$extensions = 'png';

if (is_dir($folder)){
    $dir = opendir($folder);
    while ($file = readdir($dir)) {
        if (preg_match("/^[^\.].+\.{$extensions}$/i", $file)) {
            $files[] = $file;
        }
    }
}