The normal approach would be to install your images to
PREFIX/share/pixmaps/YOUR_APP. For example Gnumeric installs some
.png files in
You can also use icons from the users icon theme.
You didn't write what component you want to use to display your images, so I'll assume
Gtk.Image has several constructors for the purpose of loading the image:
See the main documentation of
Gtk.Image for more methods. Some other widgets have similar methods to load images (for example toolbar buttons).
You should not use
from_stock any more (There was a
stock system in Gtk+ that is being replaced by freedesktop.org icon schemas).