This picture of the defaced painting, which was hanging in the Goodman Gallery in Johannesburg, was uploaded onto Twitter.
Apparently people at the gallery tried to intervene when two men tried to smear the painting.
Meanwhile hundreds of people carrying posters gathered outside the High Court in Johannesburg.
Zuma's ruling ANC went to the High Court to have the painting removed from the Goodman Gallery. The court ruled that the hearing will be broadcast live on television on Thursday.
"The Presidency is shocked and disgusted at the grotesque painting by Brett Murray depicting President Zuma in an offensive manner," Businessday newspaper quoted spokesman Mac Maharaj as saying.
Many supporters of the ANC and Zuma have been upset with the painting, calling it an abuse of artistic expression. The artist who did the painting, Brett Murray, said he never intended to cause hurt or to harm the dignity of another.
"I never intended the artwork to cause any hurt or to harm the dignity of any person," he said in statement to the court.
It was reportedly already sold to a German collector for around $14,000.
The 1.85m-high acrylic painting sparked huge online debate about freedom of expression and the right to dignity and privacy.