Follow these steps below:
1. Set up Home Sharing on your computer
In iTunes, choose File > Home Sharing > Turn On Home Sharing.
Type your Apple ID and password, and click Turn On Home Sharing.
Repeat these steps for each computer you want to use to stream content to Apple TV (2nd generation), using the same Apple ID and password.
2. Set up Home Sharing on Apple TV
On Apple TV, choose Settings > Computers.
Choose Turn On Home Sharing, and then enter the same Apple ID and password you entered on your computer.
3. Stream photos from your computer to Apple TV
Once Home Sharing is set up on your computer and on Apple TV, you can use iTunes to stream photos to your home theater system.
In iTunes, choose File > Home Sharing > Choose Photos to Share with Apple TV.
In the window that appears, select Share Photos From, and choose a source from the pop-up menu.
Choose “All photos, albums, events, and faces” or “Selected albums, events, and faces.”
If you chose “Selected albums, events, and faces,” select the albums, events, and faces you want to stream.