One thing this report shows is that Panda is complex, and whether its demotion of a site is "deserved" or a false positive, getting to the root of it is far from one size fits all!
In this case, it underscores the limitations of web search today. We've known for a long time that information only present in images, or Flash movies, or even some Ajax pages, is problematic for all search engines. Google may have made some technical advances in these areas, but the publicity has been a lot stronger than the reality.
In s case like this present one, some alt attributes might have helped earlier on - as well as some on page text. Ideally a longdesc "should" be a solution too, but it's so underutilized right now on the web that I doubt it would have any ranking impact.
What I'm wondering about is why these pages USED TO rank - and what about Panda then tagged them as unworthy.