We've discussed this via ticket, but basically it was just the externalDataUrl src/config.php setting which was pointing at your CDN so this is sorted now.
To answer the other question directly, we don't have a base image path anymore, though this doesn't apply to avatars. You will however have to ensure any references to any images in your templates are an absolute path e.g. /styles/default/xenforo/images/blah.png.