As a Windows 7 user, I find the Snipping Tool extremely useful (as does Kate). However, if you don’t have this on your computer, here are some alternatives:
Jing – Another shout out for Jing. Jing is really simple to use and best of all, it’s free. You can download from: https://www.techsmith.com/jing.html
Skitch for iPad – I downloaded this for free the other day and found it extremely easy to use and very powerful. It’s fab! Once you’re done you can share easily via email and Twitter. You can download for free from: http://itunes.apple.com/gb/app/skitch-for-ipad/id490505997?mt=8.
Screenshots on your PC – For a quick and easy way to get a no fuss screen shot of what’s on your screen simply hit ‘Print Screen o’n your keyboard. Once you hit print screen, all you need to do is paste into a Word doc, email or Paint (which comes as standard on your PC).
Screenshots on your iPhone or iPad– Press the Power button at the top right of the iPhone / iPad and the Home button at the same time for just a quick second. When you do this you’ll see the screen flash briefly and you’ll hear the camera shutter sound. The screenshot will be saved in the Camera Roll album.
Screenshots on your Android phone – As above except for longer – and the Power button is on the right-hand side.