WMF Image Format

Windows Metafile (WMF) is a graphics file format on Microsoft Windows systems, originally designed in the early 1990s. Windows Metafiles are intended to be portable between applications and may contain both vector graphics and bitmap components. Essentially, a WMF file stores a list of function calls that have to be issued to the Windows Graphics Device Interface (GDI) layer in order to display an image on screen. Since some GDI functions accept pointers to callback functions for error handling, a WMF file may erroneously include executable code.