Roger,Consider watermarks on your images. They are easy to add with Photoshop or similar software and would not hinder the information presentation. If people can't use your images, they probably won't use anything else.
In order to not hinder the information they need to be out of the way, top, bottom, side, edge frame etc.. I just came off a photog forum and all the pros agree they are useless, time consuming and really do little to no good because thieves just crop them out. A good effective watermark ruins the photo one that does not just gets cropped...
The bigger issue is that I have over 2300 images on-line with MANY of them linked to in forums so I hate to take them down. I could password protect them but then none of the forum pics work..
There is no way to add watermarks and re-post the pictures without breaking all those links!!! I have already found many of my pics that have been cropped or manipulated to not appear as mine but the software I am using is good and finds digital matches even if the pics are cropped or tweaked..