Here is what I have found so far. Anyone of them might be who you are talking about. Without knowing how old the photos are, I can only guess, so I listed all the Robert Lock(e)'s I could find in Marion County Indiana
1910 Marion County Indiana Census ED 193 Robert Locke, age 20, b. Ohio, Parents b. Ohio Ida Locke, age 22, b. Ohio, Parents b. Ohio
1920 Marion County Indiana Census ED 76 Robert E. Locke, age 29, b. Ohio, Father b. Pa. Mother b. NY Wife: Ethel Lock, age 28, b. Indiana, Parents b. Indiana Son: Robert E. Locke Jr., age 3 years and 4 months, b. Indiana
1920 Marion County Indiana Census ED 23 Robert E. Locke, age 53, b. Tennessee, Parents b. Tennessee Wife: Laura Locke, age 49, b. Tennessee, Parents b. Tennessee Son: Lloyd Locke, age 27, b. Tennessee
There are 7 Robert Locke's in the 1930 Marion County Indiana Census
It might be interesting to have someone look at the photos and have them dated if possible. Knowing about when the photos were taken would help me help you. I highly doubt this is a part of my lineage, but this is what I do, help when I can :) If you like, you can scan the photo's and email them to me, and I can post them on my web site.