Hi there! I considered posting this in the Asset Store subforum, but it seems to be a space intended only for promotion, not support.
It’s been a number of years since I’ve uploaded a new asset, and both the asset store portal and documentation seem to have changed considerably; in particular, I can’t seem to find guidance on the recommended / required dimensions for asset store thumbnails.
I’ve looked here https://assetstore.unity.com/publishing/submission-guidelines
As well as in the publisher panel, but I can’t seem to find a source of truth for all required media in just one place, and most things appear to be undocumented.
Any help finding this info is greatly appreciated! -Alex