Hi,
You can obtain the directory of the ICE executable by looking at where our shell extension is installed. The application will be in the same directory. The shell extension registration is here:
HKEY_CLASSES_ROOT\CLSID\{1AC77AE9-9EC6-405A-9F9B-C06AB3C10B71}\InprocServer32\(Default)
The value here will typically be: C:\Program Files\Microsoft Research\Image Composite Editor\ShellExtension.dll
The application is called "ICE.exe", so you can strip the "ShellExtension.dll" off the end and replace it with "ICE.exe" and you'll have the actual installed location of the application.
There is currently no command line argument for specifying the default export directory, but this (along with other command-line options) is planned for a future release.
Thanks,
Bryan
Image Composite Editor Team