For a specific, strongly contested keyword say <X>, Google shows a set of 4 image results at the top of its regular SERP for this keyword. The left-most image (first) result is an image on a page of mine, however the page itself is nowhere to be found in the regular SERP results (not in the top 100).
I would think that because the image is very relevant and useful (contains information) the page it is found on should rank decently at the least.
The site is affected by Panda. Could this by one of, if not the primary reason why the page itself doesnt rank well?
The algo has determined that it is the best and most relevant image of a widget available but the page that it is on doesn't give the visitor as much reliable information about widgets as over 100 other pages.
A gross simplification of course but that's what, in theory, the search engine is attempting to do.