Here's a pic of Lincoln Jeffries Senior in his later years alongside the other two. http://i135.photobucket.com/albums/q...djg/LJPics.jpg
Judging from the tash, hippy hair style, high forehead and cheek bones the unknown guy in the middle picture has to be LJ. If he was in his 60's at the time this would place the picture just before WW1.