OK, findings regarding iOS cover image.
Images should be rectangular, e.g. 96x96, 128x128, etc..
iPhone has two images, one - thumbnail and one big - when you click on it
for small image - 96 and 128px works. If using images bigger, e.g. 384, 512 - it will not work
for big image - works any image, e.g. 96-512
Issue - you can’t use 2 images, although specification support it
artwork: [
{
src: "https://dummyimage.com/96x96",
sizes: "96x96",
type: "image/png",
},
{
src: "https://dummyimage.com/128x128",
sizes: "128x128",
type: "image/png",
}
it will grab ALWAYS the first image. And as result - max image to support both thumbnail and big one - it’s to use rectangular 128x128!