How to sign my images?
Signing photos consists in drawing a logo or some text over your pictures. In this way you avoid situations where you lose your time by taking photos of your items, while competition "steals" your photos and uses them on their auctions.
It's a good idea to sign your photos with your eBay nickname. If you notice that your competition uses your signed photos on their auctions, you can submit a complaint to eBay, what usually results in a warning for the competitor. If the photo is not signed, then you have no evidence that it belongs to you and eBay can do nothing with the competitor.