Investigate cause of image artifacts with gain > 0

[GoogleCodeExporter]

What steps will reproduce the problem?
1. set gain > 0
2. take picture

What is the expected output? What do you see instead?
Image should have continuity from lowest to highest intensity values.
Instead, artifacts are generated where brightest parts of image are black.

Suspected cause is that MSB of 10-bit ADC capture is being stripped by AVR 
before sending to PC client.

Please use labels and text to provide additional information.

Original issue reported on code.google.com by shimniok on 9 Sep 2010 at 9:24