Long ago, we had image proxying in remarkup (see T2000 / D3908). We removed it since it was a complicated mess and the implementation was far from good enough, and it was much easier to delete than fix.
We have somewhat better infrastructure now and have seen more demand for this. To restore the feature without the issues in T2000, we can:
- Emit a link with JS metadata from remarkup.
- Enrich the link on the client, like we do with Doorkeeper tags.
- Use security.allow-outbound-http to control availability, without needing to add new config.
This will be a little bit flickery in some cases, but let us handle all the non-200 cases without doing huge blocking waits.