Something more to add - which make the problem stated above a bit more serious.
I think it would be important to limit the image sizes and file types that could be uploaded to save on server space and bandwidth. As it stands I can not find a way of limiting uploads and I am afraid site users may abuse this. It is for instance possible to upload large image files, videos even .pdf's etc. without admin being able to stop it apart from manually reviewing media content and possibly banning those who abuse it (though I think this plugin was intended for more intimate groups of collaborators, not a CMS type thing,..)
Something like the file up-loader of "User Submitted Post" or the old, now depracted "TDO Mini Forms" where admin can limit the file type, sizes and number of files and it automatically attach images to the post will make this plugin sublime.
Keep up the good work :)