Charles, Martha & George Clark

I have a picture of my GG Grandfather and family and I'm positive it's the same people in this picture as in mine. It is a family photo with George and his children. Martha died just before the picture I have was taken. If that's the case, the names are:
George Perry Clark b. Jan 31, 1859 d Jan 8, 1915 (Father)
Martha Jane (Shaw) Clark b. Dec 26, 1860 d. Aug 30, 1908 (Mother)
Charles Walter Clark b. May 3, 1886 d. July 22, 1941 (son)

If this picture was taken in 1900 it would make sence because Martha would still have been alive. The picture I have, taken in 1908-09 doesn't have Martha in it because it was taken just after she died. I also have 2 other pictures of Martha and it's the same person in this picture as is in my two.