Some video editors will allow the export of a single frame, which is at the res of the video.
Another easy way:
Make the playback window as large as you can, full screen if possible. Pause the video on the frame you want. Hit the %26quot;Prt Scr/Sysrq%26quot; key (Usually near the %26quot;F1-F12%26quot; Keys).
Now open %26quot;Paint%26quot; or whatever photo edit software you like.
In Paint, hit the %26quot;Ctrl%26quot; and %26quot;V%26quot; to paste (Or use the menu to do the same).
Crop out any unwanted borders, and size to optimize detail and clarity. Should be able to print a 4%26quot;x6%26quot; if you have decent video (720 X 480).