GIMP (Gnu Image Manipulation Program) is a popular and free open source cross-platform image editor available in versions for Linux, Windows, and Mac. It is seen as a viable alternative to Photoshop.
GIMP provides the tools needed for high quality image manipulation from retouching to restoring to creative composites. It also offers graphic design elements.
This course offers short tutorials that will help you learn how to use GIMP to manipulate and improve images.
We shouldn't be too hard on Rookie Bob! If he doesn't find good help soon, he will learn to do what most of us do to avoid any distortion that extreme: Just use the presentation software to stretch it the other way until it looks about right, chop it off here and there, and hope we don't have to ever insert images anywhere but on a slide!
A better, proactive approach is to gain control of the situation from the start! Learning to crop with the power of an image editor (such as GIMP) helps you improve the composition of your images as well as ensure a proper and proportional fit.
Let's get started!