Hello Henry,
The only pictures of the Sun taken by the Mars rovers that I know about were studying eclipses, or more accurately "transits" of Mars' moons Phobos and Deimos across the Sun. For more information, you can visit this web site: http://www.nasa.gov/home/hqnews/2004/mar/HQ_04085_rovers_solar_eclipses.html
When our Moon passes between the Earth and the Sun, we call it a solar eclipse. When one of Mars' moons passes between Mars and the Sun, we call it a transit. The angular size of the Moon and the Sun in our sky on the Earth are about the same, so the Moon can block out the entire Sun in a solar eclipse. The angular sizes of Mars' tiny moons are so small that they can never entirely block out the Sun for an observer on the surface of Mars, so solar "eclipses" on Mars are more properly called "transits."
By carefully studying the timing of the transits of Phobos and Deimos across the Sun observed by the Mars rovers, scientists can improve our knowledge of the orbits of Phobos and Deimos. Scientists can also use the shape of the shadows cast by Phobos and Deimos to learn more about how these two small moons are shaped.
Kris