Once I was watching a listing on ebay and thinking that it was a pretty good photo, and then on the last day of the listing, I realized it was my photo! By the time I reported it, the item had sold, and the seller got more than I did for my original listing! Now I have to put watermarks on all of my pictures, but I feel so bad about covering up the picture that I tend to put it in the corner, so I think they could still steal it and just crop it, plus I don't think it would be that hard to use photoshop to remove it.
On another item that I haven't listed yet, I took a picture of a black purse and it came out sort of blue, like a lot of black items seem to, so I converted it to black and white and now it looks like a stock photo. So I don't know if I should use it because even if I watermark it, people will assume I stole it.
I did have another listing with a picture of the item, and someone sent me a question asking for a picture of the real item, like I was using a stock photo. It wasn't even that good of a picture.
By the way, when I get ready to list an item I may take 100 or more pictures, trying to get the best one. So just because I have good pictures doesn't mean I stole them. I also admit that I use photoshop to correct the colors, and I often clean up my backgrounds, but I don't think that is wrong. My husband also complains about how much time I spend just creating one listing.
Anyway, my concern is that I will be accused of stealing photos because my pictures are too good.