imageresizer.php

<?php

ini_set('display_errors', 'On');
set_time_limit(-1);

$imgs = [
    '/srv/http/jessica.jpg',
];

define('BR', '<br>');
foreach ($imgs as $img) {
    $original = basename($img);
    $path = dirname($img).'/';
    $copy = '__temp__'.$original;
    copy($path.$original, $path.$copy);
    $i = 0;
    $quality = 100;
    while (filesize($path.$copy) > 100000) {
        $i++;
        $quality--;
        unlink($path.$copy);
        imagejpeg(imagecreatefromjpeg($path.$original), $path.$copy, $quality);
    }
    unlink($path.$original);
    rename($path.$copy, $path.$original);
    chmod($path.$original, 0777);
    echo "$i iterations for file $original".BR;
}