Hi,
If the site icon is more than 1 MB, the blog won't show in @zeu.dev 's potatonet.app discovery tool. They explained that if the icon is larger, it is not validating. (See: https://bsky.app/profile/did:plc:gotnvwkr56ibs33l4hwgfoet/post/3menmakbt3225 )
As per standard.site docs, the icon maxsize is 1 MB.

(If the image failed to load, see: https://pasteboard.co/hN2iAmv8smjr.png )
Maybe if the icon exceeds 1 MB, it's recompressed, otherwise, kept as-is.