Question : How to crop image blank space in php

I have an intranet web app that captures a 320X200 jpg image from a signature pad and displays it via php/apache.  What I need to do is crop the image to eliminate the blank space around the signature.  My current process displays the image in a 80X50 image tag which shrinks the actual jpg.  If I can crop the blank space around the signature, I won't get as much shrinkage on the image.  I'm sure php has a way to load an image, find the borders of the signature, and save the cropped area, but I'm new to php and haven't the faintest idea where to start.

Answer : How to crop image blank space in php

Check out below link to see if it helps?
http://lkml.indiana.edu/hypermail/linux/kernel/0206.1/0545.html