Your user profile 'wall' now has 2 photos if you care to use them: the Profile Photo (formerly known as an 'Avatar') that appears with each of your posts, and a Cover Photo. To set them, click on your user name at the upper right corner of the screen. A drop-down menu will appear. Select "Profile".
The initial wall setting shows a deep blue background where your Cover Photo will appear, with a smaller place at the lower left where your Profile Photo will appear.