Good screenshot app for straight talk lg optimus no root?

[Zombiesaurus]

I'm looking for a screen shot app that works for my phone but from what i have found all need a root (i don't know what it is or what it does so I'm not wanting to mess up my phone ) .so any good simple free sceen shot apps?

 

[stevenjudge]

Try pressing the power button and home key together you should hear a shutter sound