Jennifer Valley: Free (or Cheaper) Tool and Resources for eLearning (February 2015)
Inexpensive or free tools and resources for animation, audio, graphics, course development, and more
5 Free Desktop Image Editors for E-Learning » The Rapid eLearning Blog
Free options for image editing. I've used Picasa, Paint.net, and GIMP before, but PhotoScape and PixBuilder Studio are new to me.