I created a plane and added a Diffuse Material with an image as the texture, and a single lamp above it, using all default settings otherwise. Strangely, the plane appears as black in Cycles. I can't figure out what I could have possibly done wrong.
Do I need to tweak something? (Or is it normal for Cycles to treat a Plane with an image as not being illuminated (if there are no other objects in the scene)?)