I don't know a lot about them either. I thought you had to explicitly list the domain names that are allowed to access the images. Maybe someone who knows more about it can give their input.
For reference, here's mine:
Code:
Content visible to verified customers only.
(No space in the |wa v|)
I have mine set to show them another image in place of the one they are trying to link to. (the leech.gif path)
Example:
Code:
Content visible to verified customers only.