A lot of these features are normally handled by other services. So for videos, images, and gifs, these can be represented by a URL that's pasted in the channel

A lot of these features are normally handled by other services. So for videos, images, and gifs, these can be represented by a URL that's pasted in the channel that you can view with a web browser. The advantage of doing it this way actually makes it easier to scroll back in the chat history when you're searching for something that was posted.