Pretty-much what the other people shared.
I wear denim shorts most of the time (unless the weather drops below 30), and unlike the pictures you posted, I don't cut-off the leg portions. I wear the long, 'To the knees' variety, and buy them over-sized, so that the extra padding underneath isn't terribly visible (I'm sure anyone really looking at other people's loin-regions, would detect the *POOFYNESS*, no matter what you wore, sans a monk's robe?).
That, and shirts that are cut 'Long' (or 'Tall', in men's wear), so that most of the lower half is also covered.
All that being said-
Wearing shorts isn't truly a problem, unless you have a leak. That, is a WHOLE other situation! (been there, more'n a couple times, pray I never experience a repeat, thx.).
Good luck in your endeavors to wear shorts!
B.