Create a Thumbnail Image in PHP Using Library

<?php
// https://code.tutsplus.com/tutorials/how-to-create-a-thumbnail-image-in-php--cms-36421
// File Name : thumbimage.class.php
class ThumbImage
{
    private $source;
    public function __construct($sourceImagePath)
    {
        $this->source = $sourceImagePath;
    }
    public function createThumb($destImagePath, $thumbWidth=100)
    {
        $sourceImage = imagecreatefromjpeg($this->source);
        $orgWidth = imagesx($sourceImage);
        $orgHeight = imagesy($sourceImage);
        $thumbHeight = floor($orgHeight * ($thumbWidth / $orgWidth));
        $destImage = imagecreatetruecolor($thumbWidth, $thumbHeight);
        imagecopyresampled($destImage, $sourceImage, 0, 0, 0, 0, $thumbWidth, $thumbHeight, $orgWidth, $orgHeight);
        imagejpeg($destImage, $destImagePath);
        imagedestroy($sourceImage);
        imagedestroy($destImage);
    }
}
?>

<?php
    // Another File
    require "thumbimage.class.php";
    $objThumbImage = new ThumbImage("/web/uploads/orig.jpg");
    $objThumbImage->createThumb("/web/uploads/thumb.jpg", 125);
?>