When you publish to Facebook, iPhoto creates a new album on Facebook for the photos. Even if you publish just one photo, iPhoto creates a new album for it.
Step 1. Select the photos you want to publish.
You can select several photos, an entire event or album, a tile on the Faces corkboard, or just one photo.
Step 2. Click the Share button on the bottom toolbar, and then choose Facebook from the menu.
Step 3. In the Facebook Albums menu, choose whether to create a new album with your photos, add them to an existing album, use them as profile pictures, or post them on your Facebook wall.
Step 4. Choose publishing ...