Someone

function imageResize($maxWidth, $maxHeight, $fileFrom, $fileTo) {
    $img = false;
    if (is_file($fileFrom)) {
        $img = imagecreatefromstring(file_get_contents($fileFrom));
    }

    if($img) {
        $width = ImageSX($img);
        $height = ImageSY($img);
        $maxWidth = ($maxHeight=='*'?1000000:$maxHeight);
        $maxHeight = ($maxHeight=='*'?1000000:$maxHeight);

        if ($width > $maxWidth || $height > $maxHeight) {
            $ratioX = $width/$maxWidth;
            $ratioY = $height/$maxHeight;
            $ratio = ($ratioX > $ratioY)?$ratioX:$ratioY;

            $newWidth = $width / $ratio;
            $newHeight = $height / $ratio;
            $newImage=ImageCreateTrueColor($newWidth, $newHeight);
            ImageCopyResampled ($newImage,
                                $img, 0, 0, 0, 0,
                                $newWidth,
                                $newHeight,
                                $width,
                                $height);
            ImageJPEG($newImage, $fileTo, 80);
        } else {
            ImageJPEG($img, $fileTo, 80);
        }
        return true;
    } else {
        return false;
    }
}