Actually there's a mention since the first Unicode Emoji TR (https://www.unicode.org/reports/tr51/tr51-1-archive.html#Longer_Term https://www.unicode.org/report

Actually there's a mention since the first Unicode Emoji TR (https://www.unicode.org/reports/tr51/tr51-1-archive.html#Longer_Term https://www.unicode.org/reports/tr51/tr51-1-archive.html#Lon...) to a "longer-term goal" to support not only embedded graphics, but also "a reference to an image on a server". I'm not sure where it comes from and what's come of it; seeing as the next sentence is "server could track usage", I have the feeling it's from the editor from Google... ;) (Mark Davis)