This has to be one of my favourite vintage purchases for a while, and it was only £2 - small pleasures.
It is a photographic glass slide, so I guess a vintage negative. I love pictures of smiling people from the past, it makes them more real. From my limited fashion history, I'm presuming Victorian, but could well be Edwardian for all I know.
It's large enough to see quite well, so I can enjoy it as is, but I may investigate getting a print from it too.