python通过pil模块将raw图片转换成png图片，pil中包含了fromstring函数可以按照指定模式读取图片信息然后进行保存。

rawData = open("foo.raw" 'rb').read()
# http://www.sharejs.com
imgSize = (x,y)
# Use the PIL raw decoder to read the data.
# the 'F;16' informs the raw decoder that we are reading 
# a little endian, unsigned integer 16 bit data.
img = Image.fromstring('L', imgSize, rawData, 'raw', 'F;16')
img.save("foo.png") 

其中Image.fromstring函数的第一个参数具体含义如下

1 (1-bit pixels, black and white, stored with one pixel per byte)
L (8-bit pixels, black and white)
P (8-bit pixels, mapped to any other mode using a colour palette)
RGB (3x8-bit pixels, true colour)
RGBA (4x8-bit pixels, true colour with transparency mask)
CMYK (4x8-bit pixels, colour separation)
YCbCr (3x8-bit pixels, colour video format)
I (32-bit signed integer pixels)
F (32-bit floating point pixels)