Help, Help and feedback
My share preview hasn't updated
Share pages and their preview pictures are rebuilt every night (around 03:00 Japan time). If you just made your collection public, your link already works, but the preview picture may take until the next day to appear.
Social sites also keep their own copy of a preview for a while. If an old one keeps showing up, most of them have a tool to refresh it, i.e. Facebook's Sharing Debugger.