Rihanna Laughs Off See-Thru Pics -- Did You See My 'T**ties?'

Rihanna doesn't think she's to blame for the see-thru pics of her upper lady parts this week -- despite the fact she wore a mesh shirt with no bra -- insisting it was camera flashes that left her exposed.

The singer was out in NY last night ... happily taking pictures with EVERY fan who wanted a shot ... when someone asked if she had seen the racy see-thru pics. She replied, "You mean my t*tties?"

This time, all RiRi exposed was a smile ... as she joked, "You come up with the flash man!"

Actually, YOU came up with the flash, man ... but no complaints here.