It may surprise you then, as it did me, to learn that raptors were actually about two feet tall, feathered, and stupid.
Some of this knowledge was speculation on Crichton's part, some of it simply was not known--when the book was published it was still believed that raptors were featherless, but the knowledge of their feathers was available before the movie was made. And at no point was anything that height ever called a velociraptor.
The liberties taken with the T-Rex also demonstrate a bit of artistic license. The notion that a creature that side could move at 30 mph on land, bipedal, is pretty laughable, especially one whose vision is based on movement (which isn't true, but it was a plot point). Besides, the thing has no arms, so if it were to trip at that speed, it would die. It would just die. It's skull would be caved in, and it would cease to be. They knew this when making the movie--they had to engage in some trickery with the animation to make it appear to move as fast as it did, because they could not pull it off believably with their digital model.
Now, on the one hand, Jurassic Park is science fiction. At no point were we ever to take it as fact, regardless of the reality that people base their dino-understanding on that film. But any other action film is just as bad with the misinformation. The way certain medical devices work (defibrilators, for example), the ability of a human to walk away from a car wreck or a gunshot wound--all of these are stretched thin by our entertainment media, to the point that our knowledge of these things is completely off base.
This has a feedback loop effect, since our perception then goes on to effect further entertainment media. We come to expect in any movie that a spy agency will announce its presence by giving you a litany of information about yourself--despite the fact that it is illegal for American agencies to spy on Americans (wiretaps notwithstanding--things have changed in the past few years). Or consider this: in every movie with sword fighting, why does the sword make a metal-on-metal sound when it is pulled out of a leather sheath?
Because it would sound strange to us if it didn't, right?