There are a couple of interesting things about the image, which has been around for a while (it's easy to find blogs and videos about it that have been posted for four, five, or six years ... sorry for the rehash if it's old news to you).
First interesting thing: it "worked." On me and on my partner both. When we first looked at it we saw two human figures, embracing.
Second, the viral claim on many blogs and websites -- that scientific research has proven young people see one thing when they look at this image while older people see another -- seems to be borrowed from the artist's website ... except that the 'scientific research' part has been grafted on. Spuriously? I can say that I haven't found any trace of scientific studies that involved this particular image, but that's not exactly proof of anything.
The piece is called Love Poem of the Dolphins, and the artist who created it is named Sandro Del-Prete. The artist has a website, advertises his gallery in Bern, Switzerland, and offers a gauzy biography that describes an epiphany with a chameleon and "his study at the Academia delle bell arte" in Florence, Italy, which you wouldn't want to confuse with the Accademia Gallery where Michelangelo's David resides.
From Del-Prete's own site:
This illustration incorporates a figure/ground perceptual reversal, and is an excellent example of one’s viewpoint being primed through experience. If one is young and innocent, they will most likely perceive a group of dolphins. Adults, on the other hand, will probably see a couple in a suggestive embrace. If one has trouble perceiving the dolphins, then simply reverse figure and ground: What normally constitutes the ground (dark areas), becomes a group of small dolphins (the figures).
I don't have kids myself, so I don't have any innocents handy to spot-check the uncorrupted half of this claim. When I look at the image now I see the dolphins, and I expect you do too. Like most optical illusions, all it takes to see through the misdirection is to see through it once. The image is a neat trick, though, even if it wasn't published in the official journal of the American Academy of Pediatrics.
What did you see when you first glanced at the image? If you saw the dolphins first, how old are you? If you're older than eight, are you disqualified from participating in even an unscientific inquiry because you're a cetologist?