So right now I'm using Photoshop CS2 on my Windows 7 laptop, but I'd like to dual-boot and put a Linux operation system on there, too. I don't know if there's a Linux version of Photoshop and if there is, I don't really feel like buying it. Does anyone use GIMP that has also used Photoshop? Is it comparable? Can it be a valid substitute for Photoshop?