I think gossip should verify the 'x' field of 'imeta' tags.  At the very least.  Then maybe it should do SHA256 sums of links in posts that end in image file extensions, and include imeta tags for them with 'x' fields.  Then we can have verified images at least.

The rest of NIP-92/94/96 isn't as interesting. 

 If there is a hash, it's our duty to verify. 🤗