Keep in mind that feature suggestions should ultimately be filed at https://tickets.musicbrainz.org/browse/PICARD if you want them to get implemented. It’s fine to discuss them here, but they should get funnelled there eventually.
Isn’t the restriction based on the cover art archive and not picard?
When you upload an image the cover archive.org generates 3 images, a 250x250, 500x500 and your uploaded image.
If someone from the cover art archive team could comment if it is possible for them to generate another image size such as 750x750 or 1000x1000,
Picard could potentially process the image as well and shrink the full size image to the requested size.
I thought someone had already contacted the Cover Art Archive asking for 1000 x 1000 sizes?
Or am I wrong?
Regardless, 1k x 1k is a no-brainer these days. And it saves everyone bandwidth in the end (rather than everyone downloading crazy huge sizes - for instance I’d always rather download too big than 500 x 500…)
Keep in mind that the 250, 500, 1200 sizes for CAA refer to the longest side and do not guarantee a square (ie., 250×250, 500×500, or 1200×1200) image, just that neither of the sides will be bigger than 1200px.