For the decade that Vietnam was a nightly image on American television screens, the pictures we saw were of violence, only occasionally interspersed with some scenes of fragile beauty to highlight the suffering.

Now that the war is over - at least for us; the Vietnamese and Cambodians have taken to fighting each other around the borders - our reminders of Vietnam come mainly from memoirs by combat soldiers and correspondents plus feature films that also tend to focus on the American experience.

Compared, then, to what we have been presented before, an hour-long documentary called "Vietnam: Picking up the Pieces" to be aired tonight on PBS (9 o'clock, channels 22 and 26) is a notable departure, although many viewers may question the result. It is not, for once, about what the war did to Americans or what Americans did to Vietnamese. It is about what Vietnamese are doing for themselves - today.

The film shows reorganization of the South to conform with the requirements of communism: block committees, youth brigades, political reeducation camps and prostitute reform, as well as remnants of the older order, a privately-owned weaving factory, shantytowns, imported goods on the black market, a celebration at Christmas. The North is also depicted but there seem no major changes. The emphasis is on rebuilding.

In a sense, this program is an epilogue to the Vietnam footage that has flickered across television screens in the past. How the Vietnamese people should live - under whose leadership and according to what rules - is, after all, what the war was about.

"Vietnam: Picking up the Pieces" is the work of three young filmmakers from New York - Jon Albert, Keiko Tsuno and Karen Ranucci - who belong to the Downtown Community Television Center. They spent last December in Vietnam and shot more than 40 hours of tape, a bit of which already has been shown on PBS' MacNeil-Lehrer report and by NBC News, according to Albert.

The group has made three other major documentaries in conjunction with the Television Laboratory at WNET in New York including an award-winning film called "Chinatown: Immigrants in America." Alpert said at a preview the other day that diplomats from Vietnam's mission to the United Nations had seen "Chinatown" and that may have helped him and his colleagues in getting their visas - among the first given to American television journalists since the war.

Experienced as they clearly are as filmmakers, none of the trio had been to Vietnam previously. Perhaps for that reason the program lacks sharp comparisons and tough-minded analysis. Moreover there is no explanation of how interviews were arranged and conducted, what officials were present and what was placed off-limits. This is an important point since the tone of the film is generally so upbeat that one naturally wonders how much the Americans were really allowed to see.

Model pig farms and smiling workers offering testimonials to the new leadership are okay as handouts that come from ministries of information. But they should be so labeled.

Still, the film does have its reveling moments such as interviews with a slum family in Saigon (no one, it seems, calls it by its new name of Ho Chi Minh City) and an unrepentant youth who resists the strait-laced ways of the regime. "Vietnam: Picking up the Pieces" is certainly not the whole story of the new Vietnam. But it is, nonetheless, a welcome beginning.