Human rights watchdogs say Ahmed Humaidan was merely covering the pro-democracy protests in the Persian Gulf monarchy.
However, the appeal judges confirmed the sentence handed down by a lower court on March 26, a judicial source was quoted by AFP as saying.
The 25-year-old photojournalist, who was in court for the appeal ruling, was convicted of attacking the police station in the village of Sitra, outside the capital on April 8, 2012.
Press watchdogs, including Reporters Without Borders (RSF) and the Committee to Protect Journalists (CPJ), have urged Bahraini authorities to release Humaidan and dismiss the charges against him.
Humaidan is a winner of the National Press Club 2014 John Aubuchon Press Freedom Award.
In June, Human Rights Watch deputy Middle East and North Africa director Joe Stork said that "throwing photographers in jail isn't going to keep either the protests or the accounts of what happens in Bahrain out of the world's sight."
The International Federation for Human Rights says at least 89 people have been killed in Bahrain since the uprising began in February 2011.
Ever since, pro-democracy protests have been underway almost on a regular basis across Bahrain. The peaceful protesters demand the Al Khalifa royal family to relinquish power.