Actually I think it still works just like it did in 3.x- but the thing is it only works if avatars are stored in the database. If avatars are in the file system it won't work with either.
I'm pretty sure there is no URL- it is an often asked, never answered, question. Someone posted a function to get it (via a query) once but I don't remember anything else about it.
check out this link-
https://www.vbulletin.com/forum/show...o-CMS-Articles