Stockart threatens to sue designer John Engle for copyright infringement - on his own designs.

Techdirt has a story that would make Kafka proud ; Designer Threatened With Copyright Infringement Claims... On His Own Work.
Designer Jon Engle is accused of stealing his own designs (site is down at the moment of posting, try googles cache), what has happened is that Stockart.com has somehow gotten a hold of Jon Engle's logo portfolio, and want John to pay $275 for each one of the images they have which John has in logo's that he created for clients, since he has them on his site in his portfolio.
Wait, what?

Thankfully, I have a lot of incidental proof. I would never have thought to plan for something like this, but now I wish I had. Beyond timestamps this becomes my word against theirs to a degree. The logos on LogoPond have a date stamp showing when I uploaded them to the site. This is good, especially if the designs were stolen from my showcase. My submission date will always be earlier than theirs. Even if its only by a day, first is first. Kode ( @kodespark) suggested looking at the meta data in my source files. I didn’t know about meta data before today, but there are timestamps on the files as well. All of the meta timestamps pre-date my LogoPond submissions.
What do they have? A bill and a bulldog lawyer. They refuse to give me upload dates for any of the images in question. If they believe they’re in the right, then why would they hide that from me? I have asked time and again for the name of the artist who uploaded the stolen work. I finally received an email which is less than helpful:
“Sir, it is not a question of one artist, but several. It is quite obvious you’ve been using the site as your personal reservoir of stolen works.”