Artists that post pictures in low resolution: Why do you do that?

There's an artist I follow who posts pics that can be displayed, in full, on my 35+ year old antique computer.

That makes them very small on a modern computer - or even a modern phone - and much less nice to look at.

Why? I could understand it if you sold prints, but the artists I know who do this don't sell prints.

And I don't mean sketchy doodles that were done small to begin with, these are full-page real-media color pieces.

I don't get it.