Excluding Unused Assets?

In my game folder, I have lots of Photoshop documents for all of the art in my game, and a few other files that arent used directly in the game project, but are used in the creation of the game. 

 When making a build of the game, are these excluded?

Or, are they included in the packaging, but just not used?

Obviously I want to make my game size as small as possible.

(And, if it doesnt already, excluding unused assets would make a great feature... )

Thank you!