The president of the Palestinian Authority, Mahmoud Abbas, has pardoned a Palestinian journalist whose one-year prison sentence for insulting him on Facebook was upheld by a West Bank appeals court on Thursday, the president’s legal adviser said in a statement. The journalist, Mamdouh Hamamreh, was arrested in 2009 after Palestinian intelligence officers said they saw a photograph portraying Mr. Abbas as a traitor on Mr. Hamamreh’s Facebook page. The Palestinian Center for Development and Media Freedoms, a nongovernmental organization based in the West Bank, said that Mr. Hamamreh was not the person who had posted the photograph, nor did he share or “like” it. The president’s legal adviser said that Mr. Abbas respected freedom of opinion and expression and that he had not personally filed a complaint against the journalist.