Sign it. Bottom right (or left, but right is more conventional), sitck your name / logo there. Just like all the old canvas based artists used to do. That will force people to remove / edit out that part of the picture. Makes copyright infringment more difficult, and acts as a deterrent. Also it's good for artist identification, and will help build a 'brand' identity. Anything else is doomed to fail. There is no way to stop me from saving images of your website, if I want to do it. There can't be - to view the thing, I have to be able to get it - that's the way the web works.