Manish Vishwakarma, a 19-year-old student, said: "These pictures bring to life what we have heard all along - the terror and chaos of that night,"
In another part of Bhopal about 250 victims and activists marched three miles to the now derelict Union Carbide plant to burn some 15 effigies depicting Union Carbide, Dow Chemicals and the Indian Government. Protestors also chanted slogans against Warren Anderson, the then chief of Union Carbide who fled India to escape justice.
The daytime ceremonies followed a midnight vigil in which hundreds of survivors and relatives revisited the plant site to light candles in memory of at least 15,000 people who, according to Indian government records, died as a result of the gas.
Amnesty International said this week the tragedy and resulting illnesses like cancer had claimed 22,000 to 25,000 lives. Victims' rights activists put the figure as high as 30,000.
Dow says all liabilities were settled when Union Carbide paid a $470-million settlement - but protesters claim only part of that has reached victims.
The company says it has no responsibility for cleaning up the site or for any toxins still leaching into the ground, but the Indian government is awaiting the decision in a US court that could ask Dow Chemicals to clean the site up further.
Many surviving residents of the slums that surrounded the plant suffer from cancer, tuberculosis, poor eyesight, gynaecological problems, poor breathing and other health issues.
