Sarah Bush Johnston photograph

[RJNorton]

They do look very similar to me, too, just of/at different age. Also you could likewise ask- what is the authentication of the well-known one?

Eva, I think it's considered authentic because it came from a family member. Sarah Bush Johnston Lincoln's granddaughter, Harriet Chapman, gave a copy of the image to Herndon. I cannot recall where I read it (possibly information in Ida Tarbell's writings), but I think I read that the original was still in the possession of Harriet Chapman until the 1890s, and no one knows where it is now (or if it even exists).