South Sudan’s national journalists union said the journalists, who work with the state-run South Sudan Broadcasting Corporation, were detained on Tuesday and Wednesday.
The footage from a national event in December showed a dark stain spread down the 71-year-old’s grey trousers.
At the time, President Salva Kiir was standing for the national anthem at a road commissioning event.
The video never aired on television but has been circulated on social media.
Kiir has been South Sudan’s president since the nation gained independence in 2011.
However, the country has been embroiled in conflict for much of the past decade.
Government officials have repeatedly denied rumours circulating on social media he is unwell.
The detained journalists are camera operators Joseph Oliver and Mustafa Osman; video editor Victor Lado; contributor Jacob Benjamin; and Cherbek Ruben and Joval Toombe from the control room.
South Sudanese authorities are allowed to detain suspects for only 24 hours before bringing them before a judge.
