I mean, yes, it's a little more effort, but I think you're over playing how much effort is required. Writing a half decent readme is vastly easier than frankly any feature or bug fix. Taking a couple of notable screenshots is super easy. Writing docs is hard (I've written tons for large and complicated projects), but readmes are the easiest and including screenshots is really quite easy.

Everywhere supports markdown in readmes now. Literally everywhere I've ever hosted code. And markdown with links to images is perfectly fine even if viewed in plain text mode. They'll just click the link and view the image standalone. I've done that plenty of times, too. Every editor (plus in-browser code hosts in plain text mode) makes it easy.