[Zope] Pyhton: how get ObjectValues in Subfolders? (and their URL?) /kv

From the Zope book I have this little script which returns a list of any images from the folder where it is called.

return container.objectValues(['Image']) how can I modify it so it also searches for images inside Subfolders? and how would I ask for their URLs? if I explicitly write: return container.IMG.objectValues(['Image']) it searches in the subfolder "IMG" ... still it scans that folder only ... and I can't find out how to get the full URL of the images. thanks! 'K:?