I like to tell people that the panniers are big enough to hold a case of beer. It's just talk, of course, but over Christmas I was laying in supplies and it so happened that I did get a set of 12 beers in there. It's cans. Not sure if it would really hold 12 bottles.
Isay that I can carry a bag of potatoes one one side and a case of beer on the other. Never tried carrying the potatoes either. I use a hand basket at the supermarket, and when it's full, that's about all I can haul home on the bike. I tried bringing a pie one time, and it wouldn't stay level in the pannier, and ended up a mound of crumble when I got home. Have to be careful it there's heavy items like pop, because it will topple the bike to that side.
I used the flash, and got a glowy effect from the strip on the side of the pannier