I wonder if that's a real photo or if somebody photoshopped that.
If you are referring to the stripe/check pic (with Johnny Unusual sneaking a quick post in while you were writing), the contouring/flow of the prints in each fabric are too complex for it to be worth it to someone to invest that kind of time making it believable. I'm pretty sure it is genuine.
What I want to know is if the parents did it deliberately, or if it was a 'happy accident' for the rest of us to enjoy. From the looks of it, I'd guess it was taken in the early/mid-'60s. With living through that time, I'm not sure people were thinking about such things as 'subtle but funny family dress combos' (too busy fearing 'the big one' and mourning the loss of Kennedy).