I don't know what are proper terms to express this issue I just figured with RiotX, but I'll try to explain and show screenshots. I just figured that RiotX doesn't really show text that is sent within image too well.. like with telegram bridge or so... while Riot-desktop does just fine.
Screenshot from RiotX:

Screenshot from Riot-desktop:

You'll see the text on bottom of image in Riot-desktop, while in RiotX there is no hint of any additional/adjacent text. I'd consider this as bug.
EDIT/ADD: For complete stuff, also screenshot from telegram-desktop side:
