Why the hell does it matter whether others know you're in a relationship or not? I would guess that she probably feels like you're just using her to look good to your friends, and if that's why you want a picture so bad, then you definitely deserve it.

There could be a lot of reasons why she doesn't want her picture taken. There could be a lot of reasons why she doesn't want her picture taken with you. But maybe you're confusing "girlfriend" with "friend, whose a girl".

Does it look realistic?

I wouldn't want to take a picture either, it's not exactly a noble cause. She might think your trying to show her off as a "conquest"

Yeah.."your girlfriend"

why don't you already have a picture with your "girlfriend?"

also why do you care if your friends know you have a girlfriend. they aren't dating her, it shouldn't matter. it does make you look kinda lame and 12 year oldish. it's a little weird you have to prove it to anyone.

I had an ex like that. Run far far away from this one. If she won't do something small like that it means she is embarrassed that she is with you. Either that or you came out to look like a complete creeper.

is she ashamed of you or doesn't like the way she looks in pictures

You don't have to go that far to prove anything to anyone. If you have a girlfriend, then you know you have a girlfriend.