Look at audio + video thumbnails to see if we can make the generation of manifests quicker.

[glenrobson]

Slow example:

https://iiif.archive.org/iiif/3/taboca_201002_03/manifest.json

251 canveses.

[markpbaggett]

Just adding that some videos are 160x110:

https://iiif.archive.org/image/iiif/2/cc4ia-Polar_Plunge_Promo_-_2018%2fcc4ia-Polar_Plunge_Promo_-_2018.thumbs%252fPolar_Plunge_Promo_-_2018_000054.jpg/info.json

[markpbaggett]

The thumbnail dimensions for a video thumbnail will largely come down to the original dimensions and quality of the video file (it it's video). If we can't be sure, should we just not add w,h for a video?

[markpbaggett]

We've decided to take w,h from the Canvas. See if this is possible.