If someone posts a selfie on here, is it ok to say they are hot or compliment them physically, or is that rude & dehumanizing?

I'm confused about this, I know some people want physical compliments & others don't, or it could even be hurtful if they have serious body image issues?

But others thrive from physical compliments?

So, what about you? Is it rude or do you accept flirts or compliments from strangers for a self esteem boost?

When is it appropriate to compliment someone?

I just try to keep it tame, vague & impersonal, so people aren't offended or hurt- because the point of saying something would be to make them feel good.

It might be nice if people specify- I'm in a nonbinary group on facebook & people always post selfies and they specify "flirts welcome" "no flirts" "masc/femme compliments only" "compliments ok/not ok" "don't comment on body, just saying hi!"