Twig addon img_url

In your addon for Twig, the img_url function returns a relative URL which is useless if your URL structure is more than one segment deep. I think it should return the full path.

Locate the Twig addon implementation and the img_url entry point, then reproduce the relative-URL behavior with a URL structure more than one segment deep. The work is complete when img_url returns the full path in that case and the existing relevant checks, if any, confirm the corrected behavior.

Written by the indexing model from the issue text.