Has anyone tried to "secure" graphics so they either cannot be saved from a website or cannot be printed if they are downloaded? I have a client that wants to put thumbnails of classic car paintings on a website but prevent a visitor from d/l and printing them (he is selling the limited edition of them). Any ideas?
There's at least one commercially available (reasonably cheap) script to do this - basically the call for the image really goes to the script which then shows but protects the image. I don't know how that works about people saving the image from the cache though...
Visibly watermarking an image with a logo will mean that the user can download it but it will be unusable. In any event a 72dpi jpeg is useless for print reproduction and can really only be re-used on the web. In practice most artists have no problem puting their work online for this reason. Plus if the image is re-used (with your name and url watermarked into it) it is just more free publicity for you.
Do not 'secure' the images as such, but make them unusable in other ways: a 320x200x256 color picture at 75dpi looks good on screen, but won't be of much use when printed. Plus, using eg. jpeg compression will make it small, and virtually uneditable.