"An unknown error occurred." when changing profile avatar image I'm trying to change my profile avatar image, and I'm getting a "An unknown error occurred." No indication of what might have gone wrong. Permissions are correct on /craft/storage/userphotos and all the user directories inside. What am I doing wrong?

Error message in /craft/storage/runtime/logs/craft.log:

2014/09/13 13:39:02 [warning] [application] 404 - 
2014/09/13 13:39:02 [error] [exception.Craft\HttpException.404] exception 'Craft\HttpException' in /abs/path/to/craft/app/controllers/TemplatesController.php:59
Check the log files in craft/storage/runtime/logs and search for [error] or [warning] to see the underlying error message.