bug#56691: outline-minor-mode displays navigation arrow buttons as emojis

[Po Lu]

Lars Ingebrigtsen <larsi@gnus.org> writes:

> XPMs and PBMs are irrelevant -- virtually all GUI Emacs builds can
> display PNGs.

Virtually all, but not all.  Especially not when you are first bringing
up a port, when only PBM images are available.  Developers should always
include XPM and PBM images as a courtesy to users.  I see no reason to
use PNG images for icons instead of the traditional formats.

> It was what the Emacs survey said.

How many people responded? And even if the results are real, that
doesn't mean we should bend over our backs to support those users.