How to block a specific URL phonewide

My first thought was blocking them using AdAway or AFWall, but ironically, an adblock and a firewall are useless Most of the URLs are pictures. I can easily get their URL I ask to block it phonewide because my browser doesn't support custom adblocking Didn't even try adding some lines to the phone Hosts, because my adblock overwrites it. - A replacement for the AdAway is very well on the table (if not VPN-based), but for the AfWall, only if it's as lightweight, as well organized, free, and again, not VPN-based - My browser is Opera. Not changing that. In case AdAway can be used: If the URL needs to be a line of a host source, how should it be formatted ? Thank you ahead