This is a fabulous find! In all the years we've been doing this, this is the only garter fastener holder, made with a fancy built-in portrait that we've ever seen. There's a distinct stamp on the folding clip back that reads, "Pat May 2 1900. Pat Appld For." (The suspension bar is actually folded forward, so the stamp is to be seen in all the photos taken.)
It's our belief that this is actually a lady's corset garter holder, due to the garter's portrait holder is feminine in feeling, gold- brass-toned and petite size, with a fancy scrolled edge- this portrait would be pretty dangling from an Edwardian corset. But, it's also possible this item may be a man's suspender garter fastener holder given to him by a woman (to hold the shiny, celluloid, artist's idealized lithograph of a pretty lover or mistress close to his heart, but otherwise hidden secretly under the man's vest?) Note the dark "roots" of the lady's ostentatiously colored hair, plus the vibrant turquoise, lowcut bodice that points down to her bustline (in 1900 bodices were usually high-necked on demure ladies during the day) and the wearing of garish, socially unacceptable red hot lipcolor! (This cheekiness just wasn't acceptable or tolerated in polite society during this period.) Anyhow, this find is a rare beauty!