My entire point is that having a single portrait for the synths of any species is unrealistic because half the point of uploading is that it frees you from the prison of limited biology.
Nah. Or more, the prison might be your mortality, but social norms won't just go away. Even now you
can radically change your body, and while it's unfair, some terrible people (who may be the majority, unfortunately) will totally judge you, impact your ability to find a job and force you into a specific social circle that may or may not be what you'd otherwise pick.
So I'd expect that any civilisation undergoing such a transformation would either be rather conservative and expect you to spend your (not necessarily monetary) wealth to look as "natural" (except perhaps "perfect", or with very perfect imperfections) as possible, or swing hard to the other point, and expect something radically different to show off how "modern" they are. But eventually there would likely be a lot of conformity. Edit: the ideal to conform to might change with time and perhaps location, being essentially fashion — and say, having members of a faction look really different would be fun — but I'd still see it as limited.
I mean, the Banks update makes it almost obligatory to point out Culture — and that's exactly a civilisation that could turn you into anything from a sentient balloon to a spaceship — but choices that ranged too wildly from a relatively narrow concept of a "standard" body would make you "weird," and plenty of people people would shun you for that (remember that protagonists of most novels were actually weirdos of their societies, though).