WASHINGTON—The United States on Wednesday said it imposed sanctions on eight prisons run by Syria’s intelligence apparatus, some of which featured in graphic images by a former Syrian military photographer codenamed “Caesar” that show brutal torture. The Treasury Department also slapped sanctions on five Syrian officials who directed the prisons, Syrian armed rebel group Ahrar al-Sharqiya and two of its leaders to try to hold to account those responsible for human rights violations in the country’s decade-long civil war. “Many of the prisons designated today were highlighted in the pictures provided by Caesar, a Syrian regime defector who worked as an official photographer for the Syrian military and exposed the regime’s ruthless and cruel treatment of detainees,” U.S. Secretary of State Antony Blinken said in a statement. “Today’s action … seeks to promote accountability for the Assad regime’s abuses,” he added, referring to Syrian President Bashar al-Assad, whose brutal suppression …