The major new features in HD View Beta 2 are:
Support for FireFox. Now, if you use FireFox to browse a HD View site , then you'll be prompted to install the HD View plugin.
Auto Tone Adjust.You will now see one of these icons in the top right corner. Details of this feature is available at http://research.microsoft.com/ivm/HDView/HDhelp.htm
The basic idea is that HD View now acts a bit like the auto-gain of your camera. So as you zoom into dark regions you should see additional shadow details. It actually is more sophisticated than auto-gain and generally produces better looking images.
beta2 is smaller in size than beta1.
Check out this for sites using HD View.
HD View plugin for IE is available here.
HD View plugin for FireFox is available here.
Please check http://research.microsoft.com/ivm/HDView/HDabout.htm for more info on HD View.