> Another way of achieving this would be through customising
> imagemagick-types-inhibit or imagemagick-enabled-types, right?

Thanks for sharing, I didn't know about these.  Yes, that would be a better
workaround.

That said, there is an issue and image-mode should not try to do what ever it is
doing when loading plain text...  Not sure how we could prevent that.

-- 
Pierre Neidhardt
https://ambrevar.xyz/