I'm curious whether anyone has in fact seen a large image above the fold producing Panda-like drops when that image is not an ad.
You don't say what you mean by "large" but here's my experience. [For reference, I'm talking above the fold on a 1280x800 screen]
1,500 pages with a 400x250-300 pixel image above the fold in the center column. 300x250 adblock below the image. Any additional images below that adblock.
H1 (3 - 4 kws) and text content in the left column with a small adlinks unit after the first paragraph.
Right column contains additional on site nav links.
Pre-Panda 1, most pages on page 1.
Post Panda II, most pages dropped to 50 - 250+ for searches like kw kw for fairly common widgets.
Even very relevant queries ([kw kw] pictures) for pretty obscure widget images find these pages in 15+ at best for the most part.
[Just as an aside, for one of the most obscure of these widgets, when I first posted my images on line 10 years ago, the unquoted (kw kw picture) search for it returned 3 results, today it returns 481,000. All that time before Panda I my page for that widget was # 1 - 3. today it is #15. That's about as good as it gets for me now.]