Resize base64 image

/**
     * Get plain image with sizes of original image
     * @return string
     */
    protected static function getPlainImage($imageElement): string
    {
        $fileName = $imageElement->fileId . '-' . $imageElement->areaWidth . 'x' . $imageElement->areaHeight;

        $img = imagecreatefromstring(base64_decode(self::PLAIN_IMAGE_BASE64));
        $sourceWidth = imagesx($img);
        $sourceHeight = imagesy($img);

        $thumb = imagecreatetruecolor($imageElement->areaWidth, $imageElement->areaHeight);

        $transparency = imagecolorallocatealpha($thumb, 255, 255, 255, 127);
        imagefilledrectangle($thumb, 0, 0, $imageElement->areaWidth, $imageElement->areaHeight, $transparency);

        imagecopyresampled($thumb, $img, 0, 0, 0, 0, $imageElement->areaWidth, $imageElement->areaHeight, $sourceWidth, $sourceHeight);
        imagejpeg($thumb, $fileName);

        $imageContent = file_get_contents($fileName);

        //Clean & destroy
        imagedestroy($img);
        imagedestroy($thumb);
        unlink($fileName);

        return 'data:image/jpeg;base64,' . base64_encode($imageContent);
    }