I have to test it more, one thing I noticed in the current version is that when the upload is done the cursor moves to the end of the inserted URL. This disrupts writing a note, as my (and I guess a lot of other people) flow is:

 * Make photo/create meme/right-click save image from somewhere
 * Open Amethyst
 * Start new note
 * Press add media button
 * Start upload
 * Begin typing accompanying text

With this flow, the writing is interrupted when the upload is done.

This happens almost always, as I usually type longer than the upload takes. Unless it's only a GM :-)

Hope this helps!