# -notrials, -noalpha, -lossless

cédric (dev) said on 09/27/2017

pingo 0.9x was released with some new options to preserve data from input files. for Web usage, it is not recommended to use them — you could try profiles instead (-sN). these options can not be combined with lossy, however they fit with -sN (in this case, -sN will be used as compression level instead of profiles). also, they can have a huge impact on compression

-noalpha

this option will preserve all RGB data, even if corresponding alpha is 0. however, pingo could try in this case to perform some reductions like changing colortype, filtering or order of entries in palette. those reductions are less efficient than profiles however

pingo -noalpha -s2 image.png

-lossless

this option is a combination of -noalpha, -nostrip and -nodate. it does pretty much what -noalpha does and also preserves chunks and modification date. also, -lossless should work on irregular PNG files (like APNG)

pingo -lossless -s2 image.png

-notrials

the more strict option. it preserves from any reductions and works like a recompressor. can be useful if your images have been already reduced by another tool to do comparisons

pingo -notrials -s2 image.png

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