I first discussed the Summary tab of a Windows XP image file in tip 5549 » The Summary tab on a Windows XP image file Properties page is missing?

If you open the Properties of a TIFF/EX file in Windows Explorer, and edit the values on the Summary tab, you may corrupt the file.

This problem is due to the fact the Windows Explorer assumes that the TIFF/EX file is a TIFF file.

There is currently no fix for this feature.