Image display without window

[Nick Watts <fatalglory gmail com>]

I've seen applications (eg. mozilla and blender) display an image at startup 
without any (visible) container such as a window or dialog.

I would like to add this touch of class to my app, anyone know the easiest 
way? I tried just adding a GtkImage to a GtkWindow, removing window 
decorations with gtk_window_set_decorated() and setting the container border 
width to 0, but there is still a grey border.

thanks.