$src=getimagesize("img.gif");
$width=($src[0]/3);
$height=($src[1]/3);
print'<img src="img.gif" alt="" width="'.$width.'" height="'.$height.'" border="0">';

<?php
    /**
     * Create Small Image file
     *
     * @param   $fileName Image file name
     * @param   $smallImageHeight Height of the small Image
     * @param   $smallImageWidth Width of the small Image
     * @return  string
     * @access  public
     */
    function createImageFiles($fileName, $smallImageHeight, $smallImageWidth)
    {
        $result = true;
        $baseName = basename($fileName);
        $baseDirName = dirname($fileName);
        $smallImageFileName = $fileName.'.small';
        $bigImageFileName = $fileName;       
        $smallImage = imagecreate($smallImageWidth, $smallImageHeight);
        $bigImage = imagecreatefromstring(file_get_contents($bigImageFileName));
        $bigImageInfo = getimagesize($bigImageFileName);
        // $bigImageInfo[0] - width, $bigImageInfo[1] - height       
        if (!imagecopyresized($smallImage, $bigImage, 0, 0, 0, 0, $smallImageWidth, $smallImageHeight, $bigImageInfo[0], $bigImageInfo[1])) $result = false;
        if (!imagejpeg($smallImage, $smallImageFileName)) $result = false;
        if (!$result) {
            @unlink($smallImageFileName);
        }
    return $result;
    }
?>