I just received this e-mail from PayPal/Bigstock:

Here is your commission check, thanks for being part of BigStockPhoto.com! We received many offers for the free image of the week. We will be adding a couple more free images per week and will let you know if your image was used. Thank you, have a fantastic week. Kind regards, BigStock

Let me know if my image was used?   Don't I have to agree to this?  Or is this just a canned message that I can ignore.

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.