They are a few popular photos there, such as the fellow in a picture from the 1940's in what looks like modern dress (T-shirt with logo, modern haircut, jeans, etc.).
There are also several of a lady in the background of a 1920's silent film talking on what looks very much like a cellular telephone.
One possible answer for that one could be that a lot of our so-called 'new' technology has actually been out there for quite some time, just not released to the public until much later.
Was she one of the lucky ones who got to have one way back then...?
More recently I was looking at pictures from Bryn Mawr College, and saw these two photos (below).
I noticed that in both photos, there was a girl who looked very similar, although taken many decades apart:

Her obvious intention to face the camera as well as her expression is what caught my attention.
I just have to ask why is she doing that?

Couldn't help but think it was to meant to 'archive' her time travel for posterity.
Though the hairstyles are different, the hair color is the same, as is the body size.
The face shape is also the same, as well as the expression.
It's almost like she's 'photo-bombing' her own group picture.
Or, perhaps it's the 'impish' grin that says it all...