Instagram co-founders Kevin Systrom and Mike Krieger partied like true millionaires on the Las Vegas strip this weekend. The tech duo celebrated their mobile photo-sharing service being acquired by Facebook last week for a mouthwatering $1 billion. The 26-year-old multimillionaires hit Wynn and Encore Las Vegas on Friday night, where Jesse Waits, managing partner at Encore’s XS nightclub, took the duo to dinner at the resort’s Botero restaurant with top DJs Deadmau5 and Avicii. But before dinner, Waits appropriately posted a photo on Instagram of the group. Afterward, Systrom and Krieger went to XS to check out Avicii’s set. Onlookers told us Krieger and Systrom then held court at the owner’s table at XS before moving onstage to get a closer view while Avicii performed. We’re told the tech duo called it a night at about 4 a.m. Systrom and Krieger founded Instagram two years ago in San Francisco, and it’s signed up more than 30 million users despite having only 13 employees.