there is a 2 part bug:
1)
cant choose relative image path
cant choose default image (in input box)
cant choose no image (yes this is a feature, I know)

2)
after choosing "bad path", delete input text,
then click save
(it save without image)

there is no way to get the default image back for the default skin (or any skin) unless you know the full http: path

Fixed, removed the required full url path, you can now put in what you like

Can you reset the image back to the default without knowing the http:// path? It could be put in the manual if you like...