Hey,
Where is the default storage for the icons in a local installation of Maps
?
You should provide the name of an image file uploaded to your wiki. So if you want to use a custom marker, first upload it via Special:Upload, then use it as either Foo.png or File:Foo.png (both will work).
Cheers
-- Jeroen De Dauw http://www.bn2vs.com Don't panic. Don't be evil. --