FastStone Capture is a screenshot taking and editing application. It allows you to take a screenshot of your desktop (or a portion of it) and edit that. For example, in the image below notes have been added and sections highlighted.

LifeHacker points out that the latest version of this is no longer free, but the link below is for the “handily portable freeware version“, which is.

FastStone Capture Freeware v5.3

Popularity: 13% [?]