@philipwhite As far as I know, images on PixelFed are exactly the same than images from another instance. From what I remember, PixelFed doesn’t import images from other instances, though. I’m not sure how it works.
At its core, ActivityPub is basically just some kinds of json: one can attach particular kinds of content by providing a url of some sort. And the standard is moving. Think of the Mastodon polls, for instance: when introduced, a lot of instances and client did not support them… and they were simply ignored.
Some instances might want some specific treatment for some content. For instance PeerTube enables peer-to-peer downloads, but I’m not sure whether this is what is seen from another instance.
In short, as ActivityPub is a moving protocol, not every server will accept and send the same version of it ☺
Generalistic Mastodon instance for open-minded people. Instance Mastodon généraliste pour personnes ouvertes d'esprit.