#plebchain can help out

Not sure if you can on ZBD client.

Your same profile can be used across any Nostr clients as well.

Interoperable

You can always go to https://nostr.build, upload an image, and copy the link into a note. Then we will see it

Depends on the client you use. But, a media hosting service like satellite.earth, nostr.build or Nostrcheck.me will have to be used. (Most clients will do so for you automatically)