I did send a note tonight so we'll see what they say.
Just to clarify: I did request a payout a couple days ago, so that is not what was in doubt. But their notice about thanks for the free image was in question.
I haven't yet, but I would definitely offer a free photo. I don't think it is appropriate for an agency to randomly pick the photo from your portfolio though. I would never offer something that sells elsewhere free any where, but Bigstock wants to do the picking, so no thanks.