I've posted a new build for Simple Gallery in the downloads section (members only).

Fixed Bugs Include:-

• A fix for RSS feed in DNN 4.5+
• Added a check on the random module so that it will not display photos from albums marked as non-public.
• The default album photo will now do the following checks:-
  • Select a default photo from the current album 
  • Select a random photo from the current album
  • Select a random default photo from a sub-albums
  • Select a random photo from a sub-albums

Thanks again for all your feedback!