Because of the numerous thefts, I searched for the best solution to discourage the thieves. Actually, the most efficient is a watermark, but the dA one, heavy and too visible, ruins the pictures and many groups don't accept pictures with watermarks, we can easily understand why.
So, I imagine this subtle watermark, easy and quick to do, efficient without being too visible. I hope you'll find this tutorial useful.
I used my own photo for this tutorial