Exporting to WebP with lossless enabled on transparent files produces very ugly files that do not open in GIMP
While doing some more WebP testing since my other bug, I came across something really strange. It seems that when you export a file that has transparency with lossless enabled the plugin does some really strange things. The files open in Chrome, but do not open in GIMP. Even when viewed in Chrome, they are very ugly and contain some sort of artifacts where transparency should be. When using the lossy mode (without lossless checked), the files seem fine.
Example files: test.webp With lossless. Does not open in GIMP. Does open in Chrome with artifacts present.
test_lossy.webp Opens in GIMP and Chrome with no artifacts. Lossy, 90 image quality and 100 alpha quality.
Both files were made using the "Default" source type. My current operating system is Windows and I just barely installed 2.10.4 from the torrent file provided from gimp.org.