Is this picture of a digital camera being oversaturated by bright light source i.e. the Sun? Is this picture of a digital camera being oversaturated by bright light source i.e. the Sun?

http://farm4.staticflickr.com/3110/3147227521_396e16bcfc.jpg
It's an artifact from the digital sensor and/or the image processing in some cameras. 

There have been a number of digital cameras with this issue. E.g. here is a Sony camera where the sun turned black with a specific setting for the picture profile. (In the example video, it's the S-log picture profile at 0:49.)

Sony called it a bug, and released a fix for it. 

This artifact only affects a relatively small number of cameras, and it makes sense to think of it as a bug in the camera image processing: Yes, the sensor is oversaturated, but oversaturation is better represented as all white rather than all black. 

If you have an affected camera, it's not just the sun that turns black, it's all oversaturated highlights, like this example with car headlights.