1 The *.png and README.original files in this directory are copied from 2 libpng.org, specifically contrib/pngsuite/* in libpng 1.6.26. 3 4 README.original gives the following license for those files: 5 6 Permission to use, copy, and distribute these images for any purpose 7 and without fee is hereby granted. 8 9 The files basn0g01-30.png, basn0g02-29.png and basn0g04-31.png are in fact not 10 part of pngsuite but were created from files in pngsuite. Their non-power-of-2 11 sizes makes them useful for testing bit-depths smaller than a byte. 12 13 basn3a08.png was generated from basn6a08.png using the pngnq tool, which 14 converted it to the 8-bit paletted image with alpha values in tRNS chunk. 15 16 The *.sng files in this directory were generated from the *.png files by the 17 sng command-line tool and some hand editing. The files basn0g0{1,2,4}.sng and 18 ftbbn0g0{1,2,4}.sng were actually generated by first converting the PNG to a 19 bitdepth of 8 and then running sng on them. basn4a08.sng was generated from a 20 16-bit rgba version of basn4a08.png rather than the original gray + alpha. 21
