Cover art comparisons on uploads/CAA tab

[ROpdebee]

Supercharged CAA Edits is currently mainly focused around reviewing cover art edits. The comparison dialog is (IMO) really useful, and it may be useful to also provide it when adding new cover art.

Use cases

• When uploading new cover art, add a dialog to compare the to-be-uploaded images to any existing ones to ensure they're visually identical when higher quality images are added.
• On the cover art tab, something similar could be done. Would be nice to be able to provide a URL that gets loaded instead of having to upload a file. E.g., you're wanting to replace a low res image by one from iTunes, so you paste in the image URL to compare it to the existing one.

[ROpdebee]

Maybe I should prioritise this. I caught myself frequently pasting in URLs with the new script without actually comparing it in detail to the existing covers.

It's probably not necessary to include a URL comparison on the cover art tab itself anymore.

[ROpdebee]

Marking as blocked since this really requires a port of Supercharged CAA Edits to TS before it would be feasible.