weeeellllll, if we really want to argue semantics, technically 'yaoi' is a colloquial, it's not in any technical or official japanese dictionary i've ever seen. 'shonen-ai' is also one, a combination of words 'boy-love'. 'Hentai' itself means perverted, which as we all know has a lot of contexts, but it's often used to describe rather hardcore or explict porn (from an american perspective). The defintion of the word 'orn' in english means media whose sole purpose is sexual gratification, though contextually the word means many different things to everyone, one person would consider something porn when another would not. there is no difference in japanese regarding the words hentai, yaoi, or shonen-ai or anything like it.

so in a nutshell, i would consider that picture yaoi, not shonen-ai, and not hentai. But if you consider it shonen-ai, great.