Contest photos, expo photos and other public photos can be posted anywhere you want, especially if it is considered an event or news, which in case, these are. You choose to work the expo booth, you choose to be on that stage, you choose to go to the party and so on.
However, your image can't be promoting a product or a company, because that is a different situation, unless they sign a waiver, in which many photographers or company have the person they are shooting do so.
Lee Priest, while out of the IFBB now, has been cordial both at the Arnold and at the Ironman.