How it's done on the video upload form is very different. If it was different for photos on a previous UNA version, they scraped that idea and had a hard-coded input for uploaded photos within the Photo application, the input HTML tag is hard-coded for that title, it's not something selectable within Studio, therefore, you may not have custom settings for that field.

It's a bummer I know, welcome to the inner-thoughts of "UNA Dev", you'll just have to conform to it.