Had I not been reliably informed that the person on the left is Sarah Hammell (Great Grandma Hammell), I would not have recognized her. It is a very different appearance from the photos a lot of us have seen of her when she was a little older.

I’m going to take a wild guess and say this photo was taken around 1900. In that year Sarah would have turned 38.
But who is the person on the right? I would have no answer at all to that question, but for very faint writing on the back of the photo, which I have tried to render readable below:

You need to know that the backing board of this photo was trimmed so it would fit into one of the pockets of Addie Hammel’s photo album. This is the reason that the original “Mrs Hammell” on the right is truncated to “Mrs Hamm…”
I originally read the name on the left as “Mrs Gellars.” But when I tried to find someone with that name in the 1900, 1910 and 1920 census lists in the Albany area, I came up empty. Then I realized that what I was reading as “G” might be “S” and found someone named May Sellars who lived with her husband John at 703 E Fourth in Albany–something like eight blocks from where the Hammells lived at 122 N Sherman. I can’t be sure this is the person in the photo, but it seems likely. (The name is actually spelled “Sellers,” though it is spelled either way in different census records.) There are no other “Sellars” or “Sellers” listed in Albany in 1900, 1910 or 1920. May Sellers was about 12 years younger than Sarah Hammell, so she would have been roughly 25 in 1900. That seems consistent with how she appears in this photo.
But the real question is why did Sarah Hammell have a portrait taken with May Sellers? What were they doing together in a context where a child would have written “Mrs Sellars” and “Mrs Hammell” on the back of the portrait? Maybe I am showing my ignorance of the time, but I am assuming Sarah’s own children would not have written “Mrs Hammell” on a photo of her.
Regardless of who wrote on the back, the question remains: why did they have a portrait taken together? The thought that they taught school together comes to mind, but I don’t think Sarah was a teacher. There is nothing in the census data to suggest that. In 1910 her occupation is listed as a dressmaker at home. No occupation is listed in 1900 or 1920.
All we have is another Victorian era portrait, and another mystery. Theories, or better yet hard information, are welcome.
By the way you may notice strange spots in a square pattern across part of Mrs. Sellers’ face if you look at the full-size photo. This appears to be ink that bled through from something that was placed over the photo at some point.