defenetely image*** because with img is not so readable... people should know what your domain is about from the second they see the URL, right ?
Lets make it unanimous - image***.com The only reason to look at img*** is if the image*** is not available
I agree with image****.com SEO reasons + the simple fact that people won't type in img and wouldn't probably search for it either..
image for sure... image has 10 times more Overture results than img.. also img can be confused with the top sports agency, IMG