Tested compression quality and bit-exactness on LPCB files.
Code:
2,010,200,240 bytes jpeg -c -p %1.ppm %1.qvj http://imagecompression.info/gralic/list-qvj.txt
1,440,226,595 bytes jpeg -c -p -a %1.ppm %1.qva http://imagecompression.info/gralic/list-qva.txt
1,290,129,169 bytes jpeg -c -ls 0 %1.ppm %1.qv0 http://imagecompression.info/gralic/list-qv0.txt
1,293,859,667 bytes jpeg -c -ls 1 %1.ppm %1.qv1 http://imagecompression.info/gralic/list-qv1.txt
1,299,798,722 bytes jpeg -c -ls 2 %1.ppm %1.qv2 http://imagecompression.info/gralic/list-qv2.txt
1,210,043,117 bytes jpeg -c -ls 0 -cls %1.ppm %1.qc0 http://imagecompression.info/gralic/list-qc0.txt
1,217,125,694 bytes jpeg -c -ls 1 -cls %1.ppm %1.qc1 http://imagecompression.info/gralic/list-qc1.txt
1,222,696,140 bytes jpeg -c -ls 2 -cls %1.ppm %1.qc2 http://imagecompression.info/gralic/list-qc2.txt
In the latter three cases the decompressed images aren't bit-exact in many cases, e.g. image from http://www.imagecompression.info/gralic/PIA13862ppm.rar :
000335a5: 00 FF
// skipped 2239 lines, all ending with 00 FF
0018f677: 00 FF
Are there other sets of options for lossless compression?