basically, as long as it follows the banner contest rules
, you can use whatever picture editing program you want. Photoshop, MS Paint, Corel, Arcsoft PhotoImpression, etc. Photoshop or any other Adobe image program is best because the original photoshop image of the logo is available on the contest rules page, so its easier to work with the layers and get a cleaner look, but Adobe programs tend to be expensive. But they also have a regular jpg version there, so really any photo editing/graphics program would work.