[sciurius]

Maybe it is feasible to first implement a limited form of support. For example, simple filenames only (no path, no url) and the user is responsible that this file exists in the same folder as the ChordPro file.
I don't use Companion so I don't know if it can transfer arbitrary files.

When the user edits the ChordPro file and changes the filename of an image she is on her own. If the song is displayed and the image cannot be found just show a grey area (if sizes were specified) with a missing image icon.

If this feature is too much of a pain to add to MSPro --- well, bad luck then. There are lots of other interesting features left.

In my collection of ChordPro songs, only a few use the {image} feature, and always to include a small piece of a score, e.g.

   

A possible future inline ABC feature could do that as well, eliminating the need for these images...