Hiob Releasing beta 4 now. Fixed the https issue.
About the uploading to a specific album: imgur request the authentication to upload images to an album. The extension, for the moment, does not authenticate: while being registered with the client ID, it uploads images anonymously (not tied to any user). It would need a server side part to manage the auth process, while at the moment it runs only on the client. I'll consider adding it as a feature in the future, since I found more pressing the issue of long uploading times (due to large images taken by mobile phones, they need to be resized before uploading).