The Ubuntu Photo Lens is an official Unity Dash plugin that allows users to search for local and online photos. Users will be able to filter their searches by date. You can also see photos from Flick or Facebook accounts, even your friend's photos.
The lens is available only for the Ubuntu 12.10 (Quantal Quetzal) users. To install the Unity Photo Lens plugin, open Ubuntu Software Center, search for unity-lens-photos and install it.
You will need to restart your session after the installation.