# pbmmask > Create a mask bitmap from a regular bitmap. > See also: `pambackground`. > More information: . - Create a mask bitmap separating background from foreground: `pbmmask {{path/to/image.pbm}} > {{path/to/output.pbm}}` - Expand the generated mask by one pixel: `pbmmask -expand {{path/to/image.pbm}} > {{path/to/output.pbm}}`