Can I use the GetPixel() function to a certain size? Say I want to search for a gray area that is at least (or exactly doesn't matter) 5 pixels in diameter? Or is there a way to compare the screen to a bitmap matching what I would want? Like, I would have a .bmp and I would search the screen for something that matches it. Is there anyway to do this?
No, you can't.
You can do it manually, but it would be very slow if you used GetPixel to scan a large image.
To speed up the process, get the bitmap data first, for example with GetDIBits.
But perhaps it would be better to use AutoIt, which provides many such functions.