Cute picture, but the story isn't really what happened.
Per snopes.com: The images displayed above were taken in 2004 at the Sriracha Tiger Zoo in Chonburi, Thailand. Although the Sriracha Tiger Zoo hosts one of the world's most successful tiger breeding programs, unlike most western zoos it also offers circus- and carnival-like shows, exhibits, and interactions, including (as evidenced here) the mixture of adults and young of quite different species in the same enclosures.
In one glass room, a farrowing crate entombed a pig who, lying on her side, nourished both her piglets and tiger cubs. Across the hall, another glass room housed a female tiger, who fed piglets adorned in tiger-print costumes. This incongruous display was replicated elsewhere, where enclosures housed tigers, pigs, and dogs together.
In another area, a visitor could feed milk to a young tiger resting on his or her lap — a young tiger still in possession of his claws ... There was a tiger circus, not dissimilar from a circus anywhere else: tigers leaping through rings of fire, walking across a double tightrope, parading around the ring on hind legs, and riding around on the back of the horse.
The mixture of tiger and piglets depicted in the images above therefore was not something undertaken for functional reasons, but rather it's a common form of visual entertainment provided by the zoo for the amusement of its visitors. According to the Pattaya Mail, these tiger-pig nursing relationships have also been reciprocated to the extent that the mother tiger shown suckling piglets was herself nursed by a sow:
I often double check internet stories at snopes.com