I see you mentioning strings, which is not a good idea I think. Have you tried something along the lines of:

data = Import[file,"UnsignedInteger16"];
data = Partition[data, width of your image];
Image[data,"Bit16"]

If it is a color image you might have to use ArrayReshape or nested Partition to get the right dimensions. But using this way it should remain a packed array and therefore memory efficient...

Thank you. I am trying to avoid the larger memory footprint implied by this approach.

Thank you. That's an attractive approach. I will pursue this as time permits.

My platform is Windows, so I wonder if there is an equivalent approach in .NET/Link? Perhaps something conveniently compiled from a block of C# in a string . . .

Thank you. That was an obvious miss on my part.

It works on a smaller image (11,000 x 11,000), but quits the kernel on a larger one(22,000 x 22,000) (My machine has 32GB RAM.) Even with the smaller image, it uses an excessive amount of memory. Where MMA used ~ 732MB to create the string containing the bitmap from disk, it used about another 4.8GB to import that string into an Image using "RawBitmap" format. ByteCount of the final Image[] object was ~ 242MB. I used the following syntax, which did create a plausible image.

ImportString[bitmapString, "RawBitmap", ImageSize -> {11000, 11000}, "BitDepth" -> 16]