Bob Stevens had worked for supermarket tabloids for 30 years, pasting alien heads on celebrities and making us believe that indeed Elvis is alive. His career was cut short last October after he died from inhalation anthrax upon opening a letter laced with the fatal white powder at American Media Inc. in Boca Raton. More than 500 people attended the 63-year-old photo editor's funeral at the Unity of Delray Beach Church. The parking lot outside the church was filled with journalists waiting to catch a shot of the procession. A few shouted questions at those in mourning. Reporters were, not surprisingly, asked to exercise a little restraint or leave.