In a form-fitting dress its somewhat the opposite. If you extend the legs too far it will appear that your butt is BIGGER.
If you're wearing a tight dress I recommend you take all pics straight on just so your butt is NOT in the shot (If you don't want all attention on your donk. If you don't care, profile flicks are the best). Of course your hips are but no huge booty. To create a waist straight on in a photo put hands slightly above the hips & cross legs like myself in the photo below.
If you want to make your hips appear bigger just poke them out to one side. works like a charm. Exaggerated poses are key :)
You don't need surgery. You just have to know how to work with what you've got.