Sometimes I take pictures of musicians in concert and I post the album on their Facebook page. Sometimes they like them and repost them on their facebook timeline. I assume the proper protocol to do this, on their part, is by using the "share" function so that I can see all the following likes/comments/shares, however I notice some just download the photo and post it like that. I can't say I mind terribly, but I feel a bit of credit would be in order. Some just thank me verbally in the photo posting. I messaged one once who did not give credit at all and it was added. I started adding a faint watermark in the corner because of this. Do some people just not know how to use the share function, is it limiting in some way I don't know about, or are there other motives ? Any thoughts/ideas?