THE power of video images to shatter complacency and mobilize reform efforts has scored another victory - this time in the seemingly ho-hum world of children's day care.Three weeks ago, a report on ABC-TV's "PrimeTime Live" showed hidden-camera footage of children being mistreated in two day-care centers in New Orleans. The videotapes revealed unsanitary conditions, a lack of sufficient supervision, and general chaos. In one repeatedly-shown scene, a worker dumped a crying child head-first into a crib and then struck him several times in the face. In another, a toddler was found playing with matches near a gas stove. In the days after the program aired, parents, day-care workers, government officials, and child advocates across the country expressed alarm and outrage. Child-care referral agencies and public agencies were flooded with phone calls, and local television stations in various states did follow-up reports and hosted call-in shows. The reaction was reminiscent of emotions vented earlier this year when networks aired a "home video" taken of Los Angeles police officers beating a black motorist. In both cases, hidden video cameras captured the unthinkable. The Los Angeles beating prompted local and federal law-enforcement agencies to review past police brutality claims, among other initiatives. The day after "PrimeTime" aired, the Louisiana legislature issued a resolution ordering the state's Department of Social Services to investigate the two day-care centers spotlighted in the program. The governor earmarked $300,000 to pay for more day-care inspectors and roving teams to conduct unannounced spot-checks. "We knew we had a shortage in terms of enforcement personal, and we were working on that," says Rep. Alphonse Jackson, chairman of the House Committee on Health and Welfare, reached by phone. "But I hasten to add that the TV program added immensely to our ability to get something done." Mr. Jackson has filed a resolution to review state child-care laws and to eliminate Louisiana's dual-licensure practice, which "allows for corporal punishment and for not using some of the standard educational experiences we think ought to be included in day-care centers," he says. As of this writing, the two centers in New Orleans under scrutiny are still operating, though with noticeably fewer children. Before ABC's program was shown, day-care issues "really did not seem to be a great concern in the public or in the news," says Judy Wright, spokeswoman for the state Department of Social Services in Baton Rouge, La. But after the show, phone lines at the day-care licensing office "have been so busy, and we're having a lot more people come forth and make complaints," she says. John Armand, executive producer at WVUE, an ABC affiliate in New Orleans, says that there had been "very little" TV coverage of day-care issues in New Orleans. The station did daily coverage for nearly a week after the "PrimeTime" report. Tonight, WVUE is scheduled to air a one-hour program updating progress on legislative action and featuring a live panel discussion among day-care experts and government officials. "It takes something like this, I suppose" to prompt more coverage, Mr. Armand says. During its three-and-a-half month investigation, ABC says it went to 40 facilities in eight states. In 18 of those centers, individuals posed as "observers doing research" and attached hidden microphones and video cameras with tiny fiber-optic lenses to their clothing. Video images filmed undercover are "more compelling and riveting in a way that a long treatise, which might be more informed and accurate, would not be," says Everette Dennis, executive director of the Freedom Forum Media Studies Center (formerly the Gannett Foundation Media Center) at Columbia University. These images "have a kind of finality and credibility to them that other kinds of communication do not," Mr. Dennis adds. In 1972, Geraldo Rivera, then an ABC television reporter, filmed deplorable conditions inside Willowbrook State School, a home in New York for retarded children and adults. His report drew public attention and furthered a class action suit against the state, which was eventually successful. In that instance, as in the New Orleans story, "no one paid any attention until suddenly they were confronted with graphic, almost visceral images. Then people got excited," Dennis says. There is the possibility, however, of unscrupulous use of video cameras, he adds. "Some things can be [shown] totally out of context and can even be faked, for that matter. It's important to know that the material is being gathered by competent professional people or that it can be varified by other sources." Marlene Mishkin, a day-care center director in Boston who watched a tape of "PrimeTime" with her staff, said that afterwards, some of her teachers "came out shaking." Ms. Mishkin, however, did not approve of ABC entering day-care centers under false pretenses and filming children without parental permission. That's "slimy reporting," she says. "We don't do things that break the law," counters Walter Porges, vice-president of news practices for ABC News. Before the investigation began, he says, ABC researched laws pertaining to eavesdropping and intrusion, which vary from state to state. The story, other ABC officials say, could not have been done any other way. "In New Orleans, parents were shocked," says Olayeela Daste, coordinator of child-care resources at Agenda For Children, an advocacy organization in New Orleans. "It's terrible that in order for something to become a priority we have to look at the negative and crisis situations."