A woman signs a cross Monday that stands by others at a makeshift memorial for the victims of Saturday's mass shooting in Allen, Texas. (Tony Gutierrez/AP) Disturbing images of victims of Saturday’s mall shooting in Texas that circulated on Twitter have prompted fresh debate about whether showing effects of gun violence would alter the gridlocked political dynamic on the issue. As a warning to readers, this column will contain graphic descriptions of Saturday’s massacre. Advertisement During a town hall Monday night in Bronzeville, U.S. Rep. Jonathan Jackson compared showing graphic images of gun violence to Mamie Till’s insistence on an...