I'd say if you already got that pic you already semi know what you're doing
Definitely hit her up Friday/Sat night when there's a chance she's had a few
Try to get the talk sexual, but keep it light at first. Like try to get her on the subject without realizing it. Even if you have to start kind of corny it's better than just blasting her with an unexpected dic pic
Same thing with asking for pics, you want to kind of be on or near the subject rather than just "send noodz"
best of luck!