Hello. My name is Michael. I can help you with your question.
It will no longer export the audio if the audio is DRM protected, even if you have the rights to it. That's a limitation (by design unfortunately) in the current version of the OS.
As for photos to the AppleTV - you don't really need iPhoto involved in this. But here's what you can do to configure it for viewing.
Launch that application on your Mac, choose File > Home Sharing > Choose Photos to Share With Apple TV. In the Photo Sharing Preferences window that appears enable the Share Photos From option and then be sure that iPhoto is selected from the pop-up menu next to it. (You could otherwise choose Aperture if you had a copy, a folder of your choosing, or the Pictures folder in your user account.)
To share all your pictures enable the All photos, albums, Events and Facesoption. If you choose, instead, to share just particular albums, events, or faces, enable the next option—Selected albums, Events and Faces. If you enable this option you’ll have to select the collections of pictures you want to see from the Albums, Events, and Faces lists that appear.
Regardless of which of these two options you enable, you can additionally choose to include videos by enabling the option of the same name. Once you’ve made your choice, click Apply.
I'm not referring to the iMac.
What I am saying is that it has nothing to do with the photo application, regardless of what it is. It's done through iTunes. It's called "home sharing". Here is a more detailed explanation.
Ok. Let me know how you make out.