Get RGB color of a specific screen location

[Beat Cornaz]

I have asked this befor, but for the first time did not get any answer on
my post. So I hope you don't mind that I try again :-)

How do I get the RGB color of a pixel of an image? I know the function the
MouseColor, which gives me the RGB numbers under the cursor. What I need is
to get the RGB of a specific screen location - I need to make an avarage of
e.g. 5x5 pixels. So how do I get the RGB numbers of e.g. location  "30,200"?

Cheers, Beat