THE old saw that one picture is worth a thousand words applies to “Blockade,” a documentary about the World War II siege of Leningrad.

The infamous stranglehold on the Russian city (now St. Petersburg) by the German army went on for 900 days, during which at least 600,000 (and perhaps as many at 1.5 million) people died of starvation, disease and exposure.

Director Sergei Loznitsa tells the story using silent black-and-white footage found in Moscow’s archives. Citizens scavenge for food and water, corpses are pulled through the streets on sleds to mass graves, frozen bodies litter the bombed-out city. Only at the end, when the city has been liberated and Nazis hanged in public, do smiles return to the faces of Leningrad’s battered citizens.

The surreal images lack narration and talking heads, which is no problem. In fact, the device makes the shocking footage more compelling.

But it would have helped if there had been English-language title cards putting the images in context. Viewers, many of whom weren’t alive during World War II, are expected to know the background of what they are watching. Even so, “Blockade” is powerful.

It is screening at Film Forum with Irina Gedrovich’s “Amateur Photographer,” a compilation of photos taken by a German soldier on the Eastern front. They are accompanied by excerpts from his diary, spoken in German and English.

The candid shots came back to haunt the soldier. Based on the photos, found in the KGB archives, he was convicted of war crimes and executed.

BLOCKADE
Total running time: 78 minutes. Not rated (the horrors of war). At Film Forum, Houston Street, west of Sixth Avenue.