Using Firefox 50.0b11 beta, the template FIS is broken at the English Wikisource. When testing with Google Chrome Canary, the offset image displays correctly. The template was designed by [[User:George Orwell III]] to facilitate the display of offset images, particularly in the Popular Science Monthly project.
This is a random page of the result: https://en.wikisource.org/wiki/Page:Popular_Science_Monthly_Volume_55.djvu/360
This is a random image of the result: https://en.wikisource.org/wiki/File:Results_of_latest_1.28.0-wmf.23_ab831b0_update.jpg