This is a tintype photo of two women & two men, though in reality I'm pretty sure no tin is involved. But it is a photograph printed on a piece of metal. Tintypes and similar photographic processes were very popular from the 1850s till near the end of the 19th century. There is a lot to know about tintypes - plate sizes for one thing. The size of this one I think makes it a 1/6th plate, which I suppose means a full plate is 6 times as large. But 1/6th & 1/16th size seem to be the most common sizes of tintypes. I'm no expert, don't quote me on anything.
I like this picture, it has a ton of detail. Everybody's dressed kind of formally - perhaps a 19th century Sunday afternoon at the boardwalk. Both men are wearing the same kind of hat, the one on the left has a cigar in his had, the one on the right appears to be resting his hand on top of a cane. The women are wearing very long dresses, large hats with feathers/flowers, both are holding umbrellas (for the sun, not the rain), and there appears to be a bag of some kind of the floor next to the woman on the left.
My opinion is that this was not a planned photograph, where they made an appointment and so on. I think they just walked in, and it was taken and developed in a hurry. The backdrop of the photographer's studio is hung kind of carelessly, and everybody looks a little slanted. I don't think the photographer took a lot of time with this photograph. I've cropped the picture a bit, the actual tintype has uneven edges and is rounded on the top corners - it looks like it was trimmed hastily. I think these people were just out for some late 19th century fun in the sun and ducked into a little studio to have their picture made. It's pretty cool.
I have this listed in the eBay store, you can find it here, if you wish. At least for awhile.