Gnome menu icons
 

Where are the gnome menu icons located?
Distro opensuse 10.1

I'm using the traditional gnome menu, not the suse one. When changing themes the file system icons change but not the others. I'm not that bothered about the default icons but I've rasently added my own menu items and I don't know where to put the icons for display in the menu.

the icon menus I have found are:

/usr/share/icons
/opt/gnome/share/icons/
~/.icons/
/usr/X11R6/share/icons

Which is the default for gnome?
What is the default size of the menu icons? ie 32x32, scalable