Adding screenshots to your Kindle books is a handy way to illustrate step-by-step instructions to your readers.
Many "how-to" books I've read recently would have benefited greatly from some screenshots of what the author was talking about. This would have provided added-value to the book, and would have simplified the advice. All a reader would have to do would be to follow along with the pictures to get the results they wanted to achieve.
Better yet, those books probably would have gotten more sales because adding in screenshots will boost the book's page count. Adding pages suggests to the prospective buyer that they will get more for their money. Plus, by adding this simple fact that images are included in the all-important book description, book browsers become book buyers because they realize they are going to get not only how-to instructions but actual visual tutorials as well.
Mac users have a built-in shortcut right on their keyboard that makes it a snap. Windows users (like me) have to work at it. Here is a brief overview, plus websites to discover some of the recommended apps and utilities to make the process easier:
For Mac OS X: Press Command + Shift + 4, select the area on your computer screen you want to capture, and let go of mouse. You'll hear a click and the image will be added to your desktop. You can then move it into an open document.
For PC Windows: Windows 7 has a cool Snipping Tool. You can find it in Accessories. It's easy to learn, and you can save your screen capture in 4 different image formats. It took me just two tries to get it right.
Here's the screenshot I captured, then cropped using basic, bare-bones Office Picture Manager software. The whole process took me 2 minutes from start to finish.
This screenshot is the homepage where I found a good blog post from FreeMake.com that explores the features of Snipping Tool along with five other screen capture software programs: http://www.freemake.com/blog/6-awesome-free-screenshot-taking-tools/
In the past I've had luck using free software called ScreenHunter (I have the free version 6.0 on my laptop). It's worked well for me to find grabbing screenshots I can use in MS Word documents that eventually become Kindle books. The screen captures are not the highest quality. But they do illustrate instructions of what someone ought to see on their computer screen, or to show rankings of website search engine results.
Here is a WikiHow article on getting high-res screen captures using a Mac: http://www.wikihow.com/Take-a-Screenshot-in-Mac-OS-X