# pgmhist > Print a histogram of the values present in a PGM image. > See also: `ppmhist`. > More information: . - Display the histogram for human reading: `pgmhist {{path/to/image.pgm}}` - Display the median grey value: `pgmhist -median {{path/to/image.pgm}}` - Display four quartile grey value: `pgmhist -quartile {{path/to/image.pgm}}` - Report the existence of invalid grey values: `pgmhist -forensic {{path/to/image.pgm}}` - Display machine-readable output: `pgmhist -machine {{path/to/image.pgm}}`