AFAIK, other clients load original images directly from the source. I think some use CDNs. All this produces janky feeds if original files are large. Note that we never change any URLs at Primal. Users' notes remain unchanged. This is very important. Our clients have additional logic to try to load smaller versions from our CDN, then fallback to the original URL. Once the user selects the image, we always show the original hi-res version.