International Poster Gallery truly lives up to its name. This longtime fixture of the Boston art scene has been highlighting vintage advertising posters from all over the world for nearly a quarter century, introducing locals and visitors alike to a wide array of styles from 1890 to the present. After a long run on Newbury Street in the Back Bay, however, this purveyor of fine works on paper is moving its thousands of wares to a new storefront among the growing arts scene in the South End’s SoWa (short for south of Washington Street) district. Beginning February 1, look for your favorite Art Nouveau, Art Deco and Modernist masterworks at 460 Harrison Ave., just off the Thayer Street pedestrian walkway and adjacent to a lot with plenty of free parking.