How do you patch together screenshots to make a single image?

[beadbud]

Any photoshop style program could do that.

It depends on your OS. If you have windows you can use the 'Snipping Tool' to capture parts of a screen or the whole screen as long as it isn't enlarged to the fullness of your monitor.

As soon as you make a snip, (any size or part of the screen) it is added to your 'clipboard' and you can paste that image onto a WordPad page via paste (Ctrl + v). Then you can snip the second image and paste it below the first on the WordPad page.
From there you can adjust the size and position of the images and make a final snip from the WordPad page, which uses both images. That snip you can Save (Ctrl+S) and title and place into any folder on your computer. From there you can upload it to the internet, or what ever you want.

Hope that helps

Search for "Snipping Tool"