Fix PNG decoding of empty data chunks and short palettes, and use big-endian 16-bit tRNS - #3228

Fix PNG decoding of empty data chunks and short palettes, and use big-endian 16-bit tRNS#3228

JimBobSquarePants merged 5 commits into

SixLabors:mainSixLabors/ImageSharp:mainfrom

jafin:jf/png-chunk-split-and-transparencyjafin/ImageSharp:jf/png-chunk-split-and-transparencyCopy head branch name to clipboard