My grandmother (second from right) worked as a seamstress her entire life in various Chicago sweatshops. She was born in 1896, two months after her father died, and left school after the 6th grade to help support her mother. I found this photograph (a mounted copy print) and three other similar images, after her death in 1979.

I work as an archivist with vintage photographs every day, but this one really resonates with me, for obvious reasons. View full size.