Image support might be simulated with sixels, I guess.

EDIT: it already does.

For a libre alternative, I suggest wordgrinder.

Or, much better, groff+mom, and entr+make to run

     groff -mom -step -k < file.groff > file.pdf

Viewers like MUPDF will update the document on file changes I think.

Help on Groff+Mom:

https://www.schaffter.ca/mom/mom-01.html