Although most people on Ebay are honest reliable folk there are one or two who like to borrow your images without asking first! You may think this is a privallage or feel that you are getting the rewards you deserve for all the hard work you have put into your images. But stop and think. Have they asked permission, or have you given permission.
If the answer is no, they are in breach of your copyright which remains with you for 75 years after your death.
Should this happen you should contact the thief and explain that you own the copyright and ask for compensation for the use of the image or images, or at the very least get them to remove the image/s and appologise. If you are unsure what to charge for your copyright theft well the sky is the limit (anything you want), as they have already used it. In reallity review where the image is being used, get them to credit you with the copyright and ask a reasonable fee that reflects the images use.
Should they refuse contact Ebay or any other site or place that is displaying your image/s illegaly and get them to remove it on your behalf.
If all else fails the courts are on your side. Keep records of conversations, emails, and letters along with the original negative/slide/ or media card.
Prove the Copyright is Yours and Stop Copyright Theft