You can use a screenshot tool to take a picture of anything on your screen. It is great for making instructions, so you can illustrate each step. You can also use it to copy tables etc if you want to put them on the web or in different documents and you don't want to have to worry about the formatting going crazy when you move your work.

On a Mac you can take a screenshot by using the short cut keys command, shift and the number 4. This will save a picture (called Picture 1 ...) to your Desktop. You then need to open this in preview (double click it) and choose save as a jpeg and give it a file name.

On a PC you need to download this free programme and run the installer. Works a treat.