Gimp
GIMP is the GNU Image Manipulation Program. It is a freely distributed piece of software for such tasks as photo retouching, image composition and image authoring.
PhotoImpact Pro
PhotoImpact® Pro 13 is the ideal choice for digital photography, creative design and web graphics – all in one powerful suite. You’ll get everything you need to organize, edit, manage, and share digital photos – and so much more!
Adobe Photoshop
The Adobe® Photoshop® family of products is the ultimate playground for bringing out the best in your digital images and transforming them into anything you can imagine.
This is the most popular paid graphic program but it is expensive.