Needed to do some server side image manipulation with PHP for a custom Joomla component I was working on. Unfortunately, I was having some initial problems.
Luckily I found WideImage, and open source PHP library for image manipulation. It was great and made the whole process so much more simple for me to implement in my component.
Using it is a cinch, just check out the examples and documentation on their site. Again, this was an excellent library for me, and I highly recommend it.