Canvases with thumbnail property which is an image URL with dimensions

Each canvas has a thumbnail property which is a URL to an image. The thumbnail property includes a type but no image service.

Links:

• https://iiif-commons.github.io/fixtures/examples/thumbnail/canvas/thum_prop/v2/canvas_thum_dimensions/manifest.json
• UV 3
• UV 4
• Mirador
• Clover
• Thumbnail Panel