When the case was first revealed in the Swedish media earlier this month, prosecutors explained that the man was facing charges in Sweden because he had applied for and received permanent residency in Sweden in September 2013, after the alleged crimes were committed.
Droubi was convicted on Thursday of violating an article of the Geneva Conventions that prohibits "cruel treatment and torture" and of aggravated assault.
He told the court he was "99 percent sure he would have been killed if he hadn't participated in the video recording," according to a copy of the verdict.
The court said it would not order the man's deportation because of the situation in Syria but said that he was likely to lose his Swedish residence permit and refugee protection status pending an investigation.
The man said he risked being killed if forced to return to his home country, where the conflict first erupted in March 2011 as a popular uprising against President Bashar al-Assad.
His lawyer, Magnus Strömberg, told AFP he planned to appeal.
Droubi arrived in Sweden in the month that Stockholm announced it would grant automatic residency to all Syrians fleeing the conflict, except those found guilty of war crimes.
The Syrian war has caused a surge in asylum applications in Sweden, which welcomes the highest number of refugees per capita in Europe and expects an all-time record of 90,000 asylum applications this year.
Only two other people have been convicted of war crimes in Sweden. The first was Jackie Arklöv, a Croatian militant who in 2006 was sentenced to eight years in prison after torturing prisoners of war and civilians. He was already serving a life sentence for murder when the verdict was announced.