Sterling Alvarez, a reader of this blog, noticed a new Google Now background image that shows some buildings from downtime Miami. He's from Miami, so it's likely that Google tests a feature that displays photos related to your location. Google Now already shows custom images for cities like London and San Francisco, but they're background illustrations. The new ones look more realistic and they're pretty small, since they look pixelated.
Here's another image that's displayed in the morning: