This image of the Missouri flag is in the Public Domain and can be used freely. If you use it on a webpage, a link to http://ourworldflags.com/Missouri would be very much appreciated.

The flag of Missouri was designed and stitched in Jackson, Missouri, by Marie Elizabeth Watkins Oliver (1885-1959), the wife of former State Senator R.B. Oliver. Her design was adopted in 1913 and remains unchanged to this day.