I bought this in an antique shop in Bristol. A a group of bathers photographed in a studio against an “ocean” background. This is a Real Photo Post Card. A one-off. The Private Mailing Card (PMC) stamp block on the back, along with no division between the “correspondence” and “address” sides puts this in the 1907- 1914 range. It is an undivided back card, but, for that short period, the U.S. Postal Service allowed a message on the left side of the back with an address on the right.
And the bathing costumes are right for the era.
Then, I got a look at Frank’s feet and legs. They have had a hard time, but he’s not in the least bit ashamed of it. Looks like a family group. I can’t work out the writing, except for the “Frank” below the seated man. The word above the standing man may be “Mabel” and refer to the woman. The long word or words along the right bottom corner…well, I don’t know what that spells.