After this one, I saw one little game they made on the images, about “find the difference”, it was posted 26/08/2011 (15 days after the character one)
I’ll put the link as they might be a clue or not, but they might:
hxxps://www.facebook.com/tibia/photos/10150250338672364
hxxps://www.facebook.com/tibia/photos/10150250338667364
My theory is about either quantities (where it’s easy to count) or item ids, and it’s disposition on the matrix that is the each sqm in the image. But I didn’t advanced on that one yet.