I have been thinking a lot about this recently, as a friend made me promise to do this after her DH passed away after a short illness.
She told me to make sure that we have photographs of us as a whole family. As she only has two photographs of her whole family from the 12 years that her and her DH were together.
So.... Please take lots of photos, especially with mothers in the photos with kids, as they are often behind the camera.