WMF is also known as Windows metafile which consists of group of commands which can be used in case of a graphic requirement. All these commands help a computer to draw shapes, ovals, lines, etc.
1. A Windows metafile is a 16 bit which is compatible only with operating systems that are 16 bit and higher which includes 3, 95, 98, Me, NT, 2000, XP and Vista as on 2010 November.
2. Web browsers supports JPEG, PNG, GIF directly and not files such as WMF and EMF. Plug-in are available for download which will support the browser to display only EMF files and not WMF.
3. WMF handler is default in Windows XP that a hacker can start from Internet Explorer without a user sitting at computer. The MS05-053, Microsoft security bulletin was the reply from the company for this discovery and in case of using XP Service Pack 2 that must be downloaded and also Data Execution Prevention package which is included in it which will prevent the damage.