File>Import>Video Frames to Layers. (You will know right way if the codec is supported, either you will see the video frame or not when you do this step.)
Alt select the eyeball of the frame(layer) Now file save as. Just make sure you don't have layers selected. This will produce a file with just one layer.
If you want you can flatten first if you don't need the hidden layers. Your choice. Though I think I read somewheres on this forum that it may be better to flatten first just in case.