[olavfosse]

Emacs already let's you embed images in comments with iimage-mode

[bluGill]

There needs to pe a standard that all editors understand. Propriatory answers like emacs don't count as some of us do not have the same editor religion.

[lsllc]

Personally, I use markdown for comment content, not that IDEs do much with it, at least Markdown supports images with the `` syntax.

I think I've seen some tree-sitter grammars actually define injections such that their comment are rendered with markdown (but now I can't figure out where I saw that, maybe one of the Zed specific ones).

[criddell]

And there are Visual Studio plugins as well. I use one called Illuminated Comments to add images to my C++ comments.

[Cerium]

You can also do in-line UML rendering and display with babel+plantuml.

[kickingvegas]

TIL.