So by default photos you take do meet all those conditions - you don't need an explicit notice displayed, and someone taking your picture (without permission) from a location you gave permission to show it (such as BYC) constitutes a 'public display or performance' of your work without your permission (edit: and displaying it on their ebay listing, in this example - didn't specify before that they had to display, but that is what I was talking about). Thus a copyright infringement.
Anyway...... if you post anything on a public forum or on the internet it is not private any longer and you shouldn't expect it to be so. I'm not saying that it's not wrong...but I think you get the idea. If you don't want someone using your images, don't post them and don't be fool enough to think that anyone would stop using it even when asked.thanks the pretty much PROVES what I said. PUBLIC DOMAIN and posting something are 2 different things. a copyright expires 75 YEARS AFTER THE DEATH OF THE OWNER. then it is public domain and can be used freely by anyone without having to get permission or pay for. the use like a song.