When the picture is done properly.
I used to work in the retail and online auction industry. In fact, sometimes I was responsible for actually taking the pictures and photo editing them so that they could be put up online to sell stuff. That’s why when this photo showed up in my inbox the other day I literally had to do a double take.
Often people, and I did this sometimes, will put well known and universally understood items such as Coke cans or currency in their photos to indicate the size of an item. Sometimes we’d photograph it with a ruler so people could see the actual size of an item. Then, we’d list the dimensions of said item in the description and hope like hell we wouldn’t get a million morons who chose not to read the description or look at the photo emailing us and asking how big it was.
But this? This is new to me.

A tuna can? Really? This person is selling perfume bottles, which come is all shapes and sizes, on top of a tuna can with an almost unintelligible ruler in the background.
The best part? That dark blue bottle on the right? (That’s the one that I’m after, by the way.) That one comes in about 3 different sizes. So do most tuna cans. This photo is in NO way helpful in identifying what size the bottle actually is. I will freely admit that I have seen MUCH worse photos on both ebay and Etsy. This just happens to be one of the dumber ones I’ve received lately.
I guess it’s a good thing for the seller that I’m broke otherwise I’d be forced to email him/her and ask. But since I have no cash I’m just going to mock her/him here instead.
~Kelly