WMF (Windows metafile format) files are frequently used to produce clip art and other non-technical images that you need for drawings.
You can insert a WMF file into a drawing file as a block. Unlike bitmaps, WMF files contain vector information that can be resized and printed without losing resolution. If the WMF file contains 2D solids or wide lines, you can turn off their display to increase drawing speed.
WMF files can contain both vector and raster information. However, IMPORT uses only the vector information from a WMF file. When a WMF file containing raster information is imported into the program, the raster information is ignored.
While WMF files can contain both vector and raster data, AutoCAD-based products export only vector data.