I haven't taken a look at precisely how Nautilus does it, but it's most likely using gtk_icon_theme_load_icon[1] (or the other relevant functions). The abstract definition of this function is detailed in the freedesktop.org Icon Theme specification: References: [1] [2] http://library.gnome.org/devel/gtk/unstable/GtkIconTheme.html#gtk-icon-theme-load-icon [3] http://standards.freedesktop.org/icon-theme-spec/icon-theme-spec-latest.html#icon_lookup
thanks for the links .....