Nicolas Petton <nicolas@petton.fr> writes:

> I can reproduce the problem with `emacs -Q' on Fedora 26 with Emacs 25.3
> from the official repository.

I could actually reproduce after restarting Emacs.

The problem appears to come from ImageMagick 6.9.9.15, which is the
version currently shipped in Fedora 26.

https://bugzilla.redhat.com/show_bug.cgi?id=1502636

Apparently, the issue has been resolved in 6.9.9-18.

Cheers,
Nico