From the perspective of a writer, even posting your picture here on this forum makes it published. Given the differences between photography and writing, though, I'm not sure buyers would care: in the writing world, a publisher may very well reject your story or article because it's already published, when all you did was post it on the Net, in a non-private forum. The first serial rights are already gone.

Like I said, though, this is unique to writing, and I'm assuming it's not the same in photography. That said, I would consider your situation to be published. Published and paid is another story altogether. ;)