http://www.zdnetasia.com/news/software/0,39044164,61994896,00.htm

Amongst the benefits of HD Photo include:

• It can store 16 or 32 bits of data for each color, compared with JPEG's 8 bits, making it easier to discern shadow details or the subtle tonal variations of snow in sunlight.

• It compresses data twice as efficiently as JPEG, with either twice the quality at a given file size or half the file size at a given quality.

• It's designed to work well in camera image-processing chips, and to reduce memory requirements, it encodes images chunk by chunk without having to store the complete image at one time.