The photography industry is ridden with more objectifying legal terms between photographers and models than many industries, and while model release forms will sometimes protect a model’s rights, copyright law for photos remains in the favor of the person who took the picture and ‘fired the trigger’. This is one reason why the macaque who took his own selfie and denied ownership was such a hot topic last year ( story: http://darius.me/TrhG ).
With respect to the commons and to ‘model’s rights’ I release my images to the commons unless on assignment by a company who I’ve agreed to release ownership to. Photographers, never clutter your images with watermarks that obstruct people from seeing your work in all of its glory.
If you ‘must’ protect your images beyond what is already stated by federal copyright law, Digimarc for images is a much better approach ( FAQ: http://darius.me/1IlvbD )