For the past month, while the future home of Albany Center Gallery was being built in the Arcade Building downtown and its previous location had been relinquished, the gallery's director, Tony Iadicicco, worked out of the eight-week-old Stacks Espresso Bar next door. After a rent increase due to start this month forced the gallery to move after a decade in a building a few blocks north, on Columbia Street, Iadicicco and his board of directors, with assistance from the Downtown Albany Business Improvement District, scouted 20 locations. In recent days, with paper removed from the gallery's windows, people walking between offices, restaurants and parking, on Broadway and North Pearl, have peered in, curious about the 2,000-square-foot space that is adding vitality and visual interest to a long-empty storefront.