Solving issue appeared after Windows XP SP2
Windows XP SP2 is an important update and have introduced many security improvements. However, after installing Windows XP SP2, some graphical identity systems will be rendered to be useless.
The root cause is that these systems makes use of a special MIME type: x-xbitmap, or so called “XBM”.
XBM is originally developed by the X community. Presently it is uncommon on the web. However, banks like China Merchant Bank utilizies this format for authentication.