I tried URL filtering in ACP and blocked some image hosting sites. My suggestion is that if somebody posts a blocked URL, they should get notified about it. For example if member posts an image URL and that domain is blocked by suite, the post will be empty. Suite does not state it was blocked so member will edit post or even do another post with the same content. After that they blame admins that something is broken.

We have something similar to this planned in 4.1.17. I will post a new entry about it soon.