Lucia, thanks. Again, I have no knowledge of the alleged infringement and cannot find proof of it anywhere--other than the pixelated--and, for all I know, doctored--screenshot they sent in their ransom note. I can't imagine a judge would rule in their favor on the strength of that screenshot alone.
I'm fairly certain a judge would not do so, particularly not if you confidently stated that that image was never hosted on your server.
All I'm saying if you say "it might have been in a flash module", the next question become: Do you mean a flash module hosted on your server?
I like to look at both the "worst that could happen" and "the best that could happen". And, initially, the way you worded things, it sounded as if you could confidently state that the image was not on your server. But your later statement makes it sound like the image may have been inside a flash module and the flash module on your server. That is an image hosted on your server.
One thing you need to remember is that if they sued you, they might have access to the html and other stuff. That is: they could have evidence beyond what they showed you. So, even if you don't have evidence, they may. Moreover, if they have a screenshot and the most you can say is you have not been able to find evidence you hosted it, that is not as strong as saying you can definitively say you did not host the image.
Look what it takes to prove speeding. People get off routinely for uncalibrated radar guns and a slew of other technicalities that fall within the plaintiff's burden of proof. Seems to me a good lawyer would eviscerate this claim. Unfortunately, it looks as though I'll have to retain one now. It's really too bad. This is a major waste of human time and productivity for all parties.
Maybe a good lawyer would eviscerate the claim. But that depends on what other evidence Getty has and other factors which likely you don't know or which if you know you have not shared with us. And if you went to court, a lawyer would be expensive. That said: even if the lawyer did not eviscerate the claim, they would almost certainly get damages demanded by Getty reduced because Getty states ridiculously high values in their letters (and then they generally don't sue. Collecting whatever they manage to collect and not suing seem to be prime features of their business model.)
That said: moving away from "what is the worst that could happen" to "what is more likely to happen", it's unlikely Getty will sue you for reasons stated above. If they don't sue, a lawyer is irrelevant. But, it's not quite the slam dunk I thought initially-- so it might be that you want a letter writing program. But, if as I suggested above, it's possible Getty doesn't even really know who owned the site, or who to sue, you might not even want that. Also, if the statute of limitation is up, you also don't need a lawyer. Statute of limitations is 3 years from when they found the image.