From that picture ALONE it looks like Nasser is by far the best. Ronnie looks agitated and Flex looks too small.
However, I have the contest on video and I've got to admit (and people will disagree here) that Flex should have won this one but barely (the only one he deserved to win), Ronnie second, and Nasser a close third. It was one of the closest Olympias ever that year.