bug#47074: Replace XPM icons with Unicode codepoints in customize/widgets

[Eli Zaretskii]

> From: Stefan Kangas <stefan@marxist.se>
> Date: Thu, 11 Mar 2021 19:38:12 -0600
> Cc: 47074@debbugs.gnu.org
> 
> How would we go about implementing something like that?  Do we need to
> scan the buffer for any images and re-insert them when we change the
> font size, or can we just add an image attribute or something?

AFAIR, the display property has a way of reacting to the value of a
symbol's variable cell automatically.  Not sure the image display
property can, too, but it won't do any harm trying.  Keep in mind that
changing the text scale requires redisplaying the buffer, so Emacs
will regenerate the images anyway.