I generated bicubic and Lanczos versions in 2006. It was stated that the Lanczos one evidently came from a version of GIMP that was buggy, so I removed it a long time back. The bicubic is still there from that era. If it's wrong, I will have to redo that part of the page.
The Lanczos images in the paper should be correct.
The Lanczos images in the paper should be correct.