Send images with api

Hi! I have a binary (png) on n8n and would like to forward it to Mattermost. The Mattermost API says to use file_ids but does not explain exactly what to put inside it.

Can anyone please help?

Solution I got from reddit: So I haven’t actually tried it to be able to give you the exact example, but it looks like you have to actually upload the file first using the []( endpoint, which will give you the file id, and then you can use that ID in the api/v4/posts call.