Having two different ways to display images is too confusing. A much better and backwards compatible way could be done in either two ways: 1. nevent with internal kind and image url tlv. This would at least allow other clients to use the url if they don’t want to implement the attachment nip. 2. Keep the url and reference the metadata event id in a tag with a url index. 3. Probably many other ways that wouldn’t break anything. If you really want this to be a file attachment instead of image then you could just keep the original upload method and let users know that clients might not be able to see your image if you use a file attachment. All up to you, but damus will not be implementing this nip for image uploads, as stated before I think it’s simpler to encode this information into a completely optional small string so that its available on the post itself and so that clients can use the information to do all the hash checking stuff, but when they are ready, not forcing it on them. Cheers,