From the Johns Hopkins University page:
It is possible that another flyby target can be found and reached with
New Horizons' remaining fuel supply. And after that? Another exciting
possibility is that we can dramatically augment New Horizons'
capabilities by uploading new observing and onboard data-reduction
software once the spacecraft's flyby ...
On Feb. 13, 1990, Voyager 1 warmed up its cameras for three hours.
Then the spacecraft’s science platform was pointed at Neptune and the
After Neptune, it took images of Uranus, Saturn, Mars, the Sun, and
then Jupiter, Earth and Venus. The Earth images were taken at 04:48
GMT on Feb. 14, 1990, just 34 minutes before Voyager 1 ...