A Google Web Search Help thread reports several users not being able to see the frame at the top of the Google Image searches. I initially thought it had to do with frame busters of some sort, but it seems more wide spread than that. Maybe Google is dropping the framed image feature? I am not sure.
I personally see the frame with the "see full size image" option link:
It really seems to be that this is a frame buster type of thing going on. Frame busting is code that prevents other sites from framing you site in their site, like Google Images does after you initially click on an image result.
Forum discussion at Google Web Search Help.