2D Paint Programs
For most lessons in DigiPen outreach programs the Microsoft Paint program that comes with Windows is sufficient. However, if you want to do a lot of artwork or more detailed creations, you should set up a more full-featured editor program.
Adobe Photoshop is a common industry standard for image manipulation. You should use Photoshop if you have access to it, but the professional version is quite expensive.
Adobe Photoshop Elements
A lower-cost version of Photoshop that limits the use of some advanced features. Information can be found here:
The "GNU Image Manipulation Program" or "GIMP" is an open-source freeware package. The GIMP is often used as the freeware alternative to Photoshop, but it is not an exact clone and has some different features. The GIMP installer can be downloaded here:
Paint .NET is a simple-to-use, freeware program that contains most of the basics needed to create art assets for your games. It supports multiple layers, "undo" of multiple actions, transparency, rotation, cropping, and saving in multiple formats. If you are new to image programs and have used Microsoft Paint, Paint .NET is a great place to start.
http://www.getpaint.net/download.html (main site)