A CellRendererPixbuf can be used to render an image in a cell.
It allows to render either a given Pixbuf (set via the
pixbuf property) or a named icon (set via the
icon_name property).
To support the tree view, CellRendererPixbuf also supports rendering two alternative pixbufs, when the
is_expander property is true. If the
is_expanded property is true and the
pixbuf_expander_open property is set to a pixbuf, it
renders that pixbuf, if the is_expanded property is
false and the
pixbuf_expander_closed property is set to a pixbuf, it renders that one.