Currently, you can disable all media previews on your chat for yourself, but everyone else still sees them. You can also click the little X button to remove a media preview while typing or after sending the message. However, constantly removing the media preview is EXTREMELY tedious, especially in places like the #helpdesk-volunteers channel where we are constantly dropping links for people. We would very much like the ability to send chat messages without media previews by default. Ideally, there would be a "generate media preview" button that does the opposite of what the X button does now, but even if we don't have a "generate" button I would still very much like to disable media preview generation by default.