Описание тега wmf

A Windows metafile (WMF) is a vector image file format which consists of a collection of records that can store an image. The stored image can be rendered by parsing and processing the metafile structure.

The Windows metafile begins with a header record, which may include the version of the metafile, its size, and the maximum number of objects that are defined. A metafile with its records defines the steps to read the final image and hence can be "played back" when its records are converted to graphics commands and executed by a graphics API to render the image.