Fabrice Popineau <fabrice.popineau@gmail.com> writes:

> My point is that only one of imagemagick and libpng will handle png
> files at a time.  When ImageMagick is available, it supersedes png,
> jpeg and anything it handles (AFAICS).

No, the used library depends on the image-type, i.e.

(create-image "foo.png" 'imagemagick)

    vs.

(create-image "foo.png" 'png)