Where are the microphones for the black box located in the cockpit?
The headsets worn by the pilots have a microphone arm. These audio channels are split and routed to the black box.

Additionally, there is at least one microphone embedded in the cockpit, usually overhead.

The black box can support recording of up to 4 audio channels, so each channel can be examined separately.

Since the headsets and overhead microphone are inside the cockpit, stereo audio is available.

Can't find any pictures for you, sorry!

Seethis sources:

Avstop

FAA (pdf)