Use getPNGHeaderInfo() instead of decoding entire image
Use getPNGHeaderInfo() instead of decoding entire image

Only the color type from header is needed here

PKRoma/zopfli,unknownbrackets/maxcso,google/zopfli,PKRoma/zopfli,unknownbrackets/maxcso,google/zopfli,google/zopfli,unknownbrackets/maxcso,unknownbrackets/maxcso,unknownbrackets/maxcso,PKRoma/zopfli,unknownbrackets/maxcso,unknownbrackets/maxcso