@helge An alternative to digestMultibase is digestSRI (mentioned in VC spec), but digestMultibase seems to be more popular among VCDI spec authors and unlike digestSRI, it is now in security context.

Regarding width, height, digest and others: perhaps these properties should be added to url? One image may have multiple representations, for example low res and high res. IIRC PeerTube provides videos in multiple variants and has a long array of links in url.

{
  "type": "Image",
  "url": [{
    "type": "Link",
    "href": "https://example.social/image.png"
    "height": 2000,
    "width": 2000,
    "digestMultibase": "zQm1"
  }, {
    "type": "Link",
    "href": "https://example.social/image_thumbnail.png",
    "height": 100,
    "width": 100,
    "rel": "https://example.social/ns/thumbnail",
    "digestMultibase": "zQm2",  <- different digest!
 }]
}