Using LibTiff from C# (to access tiled TIFF images)

You can try our LibTiff.Net. It is free and open source version of LibTiff written using managed C#. API of our implementation kept very similar to original one's.

https://bitmiracle.com/libtiff/

We've just released it, so there may be bugs. But full source code comes with a number of test, so most obvious bugs should be fixed.

WIC provides support for very large image files. There's a nice wrapper for it in the .NET framework: TiffBitmapDecoder.