Photoshop is a good program for imaging, but if you want to get full use of the editing it will cost money.
I know alot of webdesigners and people in digital imaging who like opensource programs.
GIMP is a good program (according to others) and it is free and fairly easy to use
http://www.gimp.org/ I dont know if thats exactly what you need, but it should help a bit.
Poolshark