No, but it helps ... seriously, I would love to love Gimp and InkScape and I check up on them every few years to see if I can reasonably make the switch from Adobe products but it still seems like it would be hard.
You don't need expensive or costly Adobe products to make art.
- Gimp still doesn't have the equivalent of Photoshop's layer styles. (As far as I know, someone please correct me if I am wrong. Seriously, I'm interested in hearing if I'm wrong about this...).
- InkScape is still lightyears behind Illustrator (imho) and further once you've committed to photoshop for raster you really want illustrator for vector because they work well together for obvious reasons.
2. may not be important depending on whether or not you have any need of vector graphics, which mostly depends on the style of art in your game, but, that said, vector art, if you are comfortable and quick at making it, is often helpful as a tool used in the process of creating raster art. For example, you need a curvy scalloped frame around the game board area of a puzzle game: create the curvy scalloped frame shape in Illustrator, import it into photoshop as a layer, style the layer in photoshop. Yes, it could all be done in PS but Illustrator is easier.
Basically, my position is that if you are a programmer and good at art and want do your own art for a game that requires a lot of 2D, don't dismiss out of hand getting Adobe products because they are super expensive. You can legally get Photoshop and Illustrator without breaking the bank:
- Lower your expectations about how cheap is cheap.
- If you are a student or a teacher, or know a student or teacher who owes you a favor, buy the latest version of the Creative Suite with the student discount.
- Otherwise, buy the creative suite that is a few versions older than the current version as a download from an online discount software store. These sites seem shady but are legit as far as I know or anyway I've never had a problem. I can, for example, personally vouch that bargainsoftwareshop.com will not rip you off and I'm sure that if they were doing something illegal Adobe would have shut them down.