First of all, thank you for the great plugin!
I have a couple of issues and a couple of suggestions.
1. Whenever a user uploads a new photo random text/numbers are being appended to the filename. i.e. choko.jpg becomes choko-58229c7a35b9eb7bc534c494bf909e0d28e622f2.jpg I see no apparent reason to add these to the filename.
2. Whenever you approve the photo, it takes a while to appear. (using Firefox) I've tried clearing browser cache and refreshing page with no luck. It can take up to an hour or more to appear. It's the same thing when you delete a photo. (this might be a NextGen issue?)
3. As mentioned in other posts, it would be nice for the email notice to contain more information especially where the photo is (gallery ID isn't good without a title/name)
4. Ability to customize the online messages (i.e. Your image has been successfully uploaded) and possibly add a redirect?
5. The form/fields show up as "code". I would prefer a custom style sheet.