Hi Thomas, sorry to hear someone has done this to you. I agree with Ted, nice collection you have.
The images on ebay are the same as yours, but what surprises me is they appear to be manufacturing the prints without any photoshopping to your images ie leaving the image as is, warts and all, eg including paper weights, poster damage. They must be bulk finding images, and near automatically turning them into auctions and assuming there is value in even a small percentage actually being sold.
I agree with Rich, watermarking is part of the solution for prevention of image theft, sadly, and likely the best solution. Sure some watermarks can be easy to remove as Mel once showed, but others can be difficult near impossible to remove, however saying that, don't count on that always being the case with technological advances. Watermarks also don't need to be as prominent as on emovieposter, they can be less noticeable and more effective in preventing reproduction. It is just sad we can't show off our posters in their full glory, if we are concerned about them be used by others.
I notice you have, in Bruces terms, supersized images. That is likely what led them to your site, and made it worth their while, eg doing a search on the web for supersized images is easy. They probably have a mostly automated process. It is great to be able to show off posters in all their detail, but, to prevent the likes of moviegoods, maybe providing smaller images may be required. Your supersized images are about 3000px tall, which gives them about 75 dots per inch for a 40" print, which they could then blur a bit to smooth out. It would still look not very good, but maybe ok to old people losing their sight. For other collectors who are also showing off their posters online, it may be best limiting the size of their images to 1500px, to greatly reduce the chance of your images being turned into 40" prints. Though even 1500px size or smaller can still be made beautifully into smaller products such as 'Mini Pill Containers' and other things I have seen on eBay.
Reuse of easily taken images from the web will likely be impossible to prevent, just like trying to bring an end to illegal music/software downloading and sharing. Sure, some people will be chased, but it is just a drop in the ocean what gets prevented. Because of these people who use images without permission/credit, generally being inconsiderate, will unfortunately (as has been mentioned previously) result in some sites with great sources of images removing them or embedding watermarks or charging for their viewing.
