dude...its very simple..
one day...after uve done bangin her...
when ur in bed....(this is when girls are most honest, coz they think theyve made sensual love to their man..)
just ask her straight up..
its been bothering me a lil..i saw a pic of you at a club on d dudes lap.whats goin on?
dont give her an ultimatum at that point..let her answer..if shes stuttering or you feel its a lie..you can give her the ultimatum..
i cant tell you what you can n cant do...i was always attracted to you coz you were slightly mature than the other girls..but if i was mistaken or you do things that cross the line, dont expect me to be standin around.
this way...2 things..uve just fvkd her which means ur already on a high...so if you leave now you'd leave knowing you got the only thing she has to offer before you left...
but!...i also agree with some of the other guys here, it may just be innocent..
We dunno your girlfriend from a monitor, she could be the type thats friendly towards everybody but just stays friends or could be one of the girls one of the guys here has been with...we dunno..
i used to date a chic that was very good friends with my friends possing in pictures and hugs to say hi etc, she used to give me shoulder rubs infront of everybody(she was a proffesional trained masseuse) she used to give it to my girl and guy friends too but i knew she wasnt tappin any of them!
there are girls out there who are just out to have fun and dont see stuff like this as a huge issue.they just live in the moment and specially when pics are taken.i used to have a HOTTTT (9)friend who used to throw her legs over the guys shoulder (havin them kneel) or waist and pull her skirt up..but she never fvkd any of us.lol..then theres the lesbian with the big boobs that pulls her t-shirt up over the curve of her tits when shes takin pics wit a guy and sticks her tongue out clingin on to the guy...but shes lesbo and her 'gf' always laughs at it.lol
on the other hand..he probably had a boner and wouldve gladly bent her over...so i dunno..only you know so you need to ask and get info.