ImageJpeg

Hello, I am using PHP 4.04 for windows as a cgi with the Website 2.5.8 server. I would like to resize some JPEG images. I see the int imagejpeg (int im [, string filename [, int quality]]) function to write a file. But the "quality" is not described in the manual I have. 1) Are the "Image" functions available in PHP 4.04 for win? Do I need to do anything special to use them? Is there a way to tell which if not all of the functions in the manual are actually available? 2) What is the quality range? Are higher numbers better quality/less compression? 3) Has anyone used these functions in PHP 4.04 Win? Thanks, Barry.