Not sure if this is a bug or just a very annoying feature, but I can't get an image to appear on any of my buttons in Glade Designer.
Is there some property I need to change in order to force it to display the image?
I believe this is because by default (not sure if it's a GNOME-wide or GTK setting), no images are shown in buttons, so I'm not sure there is a way around it, either.
This Stackoverflow question hints at stock images not shown in buttons because of that, which I assume it applies to custom images too.
You might try the workaround mentioned in that question to see if it works for you:
from gi.repository import Gtk
settings = Gtk.Settings.get_default()
settings.props.gtk_button_images = True
What I have also noticed is that toolbar button images are not affected by this setting and are always shown. Simply make sure to prepend ../media to the image path in Glade, as Garry Cairns is mentioning in his answer.
