If you need a nation's flag, go to Flags and Maps of the World. You can locate your country by its continent. Then click on that country's flag and you'll get a large color image of the flag plus a map of that country.
If you need to print an image of a flag only, try Flags of the World. You can click on the country and then click on the flag to get an image of the flag on a white background with no text or additional images. (To print, go to "File" and then "Print" on your Web browser's menu bar.)