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