There are three ways to get a file into a channel's media library.
1. Upload button
From the Library view, click Upload and pick a file. You can optionally drop it into a folder by typing a folder name before uploading — folders are virtual paths, not separate buckets.
2. Drag and drop
Drag a file directly onto the library grid. The upload starts immediately and the new item appears at the top.
3. Drop page
Every channel has a public-ish Drop page at /usr/channel/<channelId>/storage/drop for quick handoffs from other devices. Toggle its visibility from the Drop page itself — it's off by default.
Inside the editor
The article and page editors have their own image picker that opens the Media view in a dialog. Uploads done there land in the same library and are immediately available everywhere else.
See also: Browsing the library.