5 bits per pixel, no alpha

gistfile1.m

static const CGBitmapInfo kDefault16CGBitmapInfoNoAlpha	= (kCGImageAlphaNoneSkipFirst | kCGBitmapByteOrder16Host);
CGContextRef CreateCGBitmapContextForWidthAndHeight(void *data, unsigned int width, unsigned int height)
{
	CGColorSpaceRef	colorSpace	= GetDeviceRGBColorSpace(); // function to get static color space instance
	CGBitmapInfo	alphaInfo	= kDefault16CGBitmapInfoNoAlpha;
	return CGBitmapContextCreate(
								 data, 
								 width, 
								 height, 
								 5, /* Bits per component */
								 width*2, /* Bytes per row (3 components per pixel, 5 bits per component, 15 bits per pixel (round up to 16), 2 bytes per pixel) */
								 colorSpace, 
								 alphaInfo
								 );
}