....interesting argument however if you do an image search for something on Google you will often come across pictures of items you may have bought and sold on eBay or other sites. I have seen quite a few vintage synths that belong or have belonged to me, appearing in these image searches and often reappearing in listings. I'd only be worried if they were selling something I still owned and 1) weren't acknowledging it as an example of a piece of kit ie 'looks something like this' or 2) it was clearly fraudulent and they were just trying to make a quick buck from an old listing - I have reported this kind of activity in the past. If I'd sold it them I wouldn't be too worried if they'd used my pics but its good practice to acknowledge that in the listing. You often see this on here 'apologies to ...... for using their pics, hope that's ok' etc. a nod to the original 'author' of the pics is a welcome courtesy.