More info about Greenshot
If the user needs to add annotations, highlightings or obfuscations to the screenshot the built-in image editor can be used. Greenshot's image editor is a basic vector graphics editor; however, it offers some pixel-based filters. It allows to draw basic shapes (rectangles, ellipses, lines, arrows and freehand) and add text to a screenshot. Special filter tools are present to highlight text or an area, as well as obfuscating tools (blur / pixelize) which can be used to wipe out sensitive data from a screenshot. Each tool comes with its set of settings, e. g. line color and thickness or an option to drop a shadow.