Doesn't work for file attachments

[Renari]

Attach an image, type /spoiler and send. You'll get an empty spoiler block and your image will disappear into the void.

[forkwhilefork]

I also have this problem on server version 5.20

[moussetc]

Thank you for the feature request. I don't know yet if that's something that feasible with the current Mattermost plugin system, but I'm looking into it.

[moussetc]

I'll keep this feature in mind but sadly, as of now there's no way for the plugin to access any attachments of a slash command.
It doesn't look possible either to upload files via an interactive dialog popup.
I don't really see a workaround 😞 I'll keep the issue open, though, in case I find one or if a Mattermost update makes it possible!