Note that version and profile are now required parameters. Some minor changes have been made as a result of comments on the almost final version. It can handle vector graphics and images. It stores pictures in a way which is independent of any particular software, computer or graphics device. Currently, the valid image types are JPEG, and GIF, both raster or bitmap type image files.
Vector images allow for greater detail and clarity at multiple zoom levels.
Also, they are usually much more compact than the equivalent bitmap. The CGM can be used to exchange pictures between different types of applications. There are a number of public domain CGM generators and interpreters available. The versions are upward compatible in the sense that a valid Version 1 metafile is a valid Version 2 metafile, Version 2 is a subset of Version 3, and Version 3 is a subset of Version 4. The version number in this parameter must be the same as the version number within the CGM file itself.