I'm beaten by an image problem

Hi Guys and Guyesses,
It should be so simple to do this but I have tried every which way but loose and I get slapped by a monkey every time, .

My problem is that I am using CMD - Shift - 4 to get the crosshairs up to take a screenshot of a section of an image. Doing this saved the image I wanted to the Pasteboard. The bad news is that I can't get the saved image to appear on either Gimp or Seashore. The "Paste" option is greyed out.
Am I doing something wrong?
Any ideas, hints or tips appreciated.
Steve

Command-Shift-4 doesn't copy it to the clipboard - it saves it to the Desktop. Take a look there for the picture. If you want it to be saved to the clipboard, hold down control: Control-Command-Shift-4.

DOH!!! ... I knew it would be something that I was doing wrong, lol.
Cheers, Van smith.