A textual representation of the image. This could be the alt text of the image, the filename of the image, or some kind of content description for accessibility e.g. ‘image attachment’.
OptionalfileRequired if the file is encrypted. Information on the encrypted file, as specified in End-to-end encryption.
OptionalinfoMetadata about the image referred to in url.
One of: [m.image].
OptionalurlRequired if the file is unencrypted. The URL (typically mxc:// URI) to the file.
Content format of media events with msgtype
m.imageSee
https://spec.matrix.org/v1.9/client-server-api/#mimage