Actually, the Heucheras happened because I imported the Heuchera database from Cubits.org this morning.
So, if you had an image in that database, it got added here, as well. But I tried to remove the duplicates that I could find.
Other than this, there shouldn't be duplicates coming in from the forum import unless the user uploaded it directly into the database and subsequently someone else proposed it to be imported, which will hopefully be a more rare occurrence.