You techy smart butts be quiet and don't tell me you knew this and I am the last to find out.
Just accidentally took a screenshot on my iPhone.
When I did it, had no clue how I did it.
Here is a link for "how to".
You can do a screenshot of any image showing on your phone.
http://www.on-a-mac.com/2008/07/12/iphone-screenshot/