Greenshot - Greenshot is a free and open source screenshot tool that allows annotation and highlighting using the built-in image editor.

Teachable - Create and sell beautiful online courses with the platform used by the best online entrepreneurs to sell $100m+ to over 4 million students worldwide.

Shutter - Shutter is a feature-rich screenshot program.

Clever - syncing between education applications for K-12 schools

Snipping Tool - Use Snipping Tool to capture a screen shot, or snip, of any object on your screen, and then annotate, save, or share the image

Claroline - Claroline is a collaborative eLearning and eWorking platform.