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. 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 . . .

I doubt that you can use C#. LibraryLink requires using C or C++. C and C++ work just fine on Windows. The Windows API is C based too.

You can use MathLink from C#, but transferring the data through MathLink will likely trigger expanding each integer to 64-bits, even if it's never greater than 255.

But have you tried the RawBitmap import format? http://reference.wolfram.com/language/ref/format/RawBitmap.html (I have not tested it.)