Some followup tests for lossless photo encoding

  $ real_time() { command time -p sh -c '{ "$@"; } 2>&3 >&2' argv0 "$@" 3>&2 2>&1 | sed -n 's#^real ##p'; }
  $ magick identify DSC00191.ppm
  DSC00191.ppm PPM 5492x3672 5492x3672+0+0 8-bit sRGB 57.6972MiB 0.090u 0:00.042
  $ for s in 0 3 6; do real_time magick DSC00191.ppm -quality 100 -define heic:chroma=444 -define heic:cicp=1/13/0/1 -define heic:speed=$s DSC00191_s$s.avif; done
  76.71
  12.80
  1.73
  $ real_time magick DSC00191.ppm -quality 0 DSC00191.jp2
  3.315
  $ real_time sh -c 'magick "$1" -define png:compression-level=0 "$2" && oxipng -q -o2 -s "$2"' argv0 DSC00191.{ppm,png}
  7.746
  $ for e in 3 6 9; do real_time magick DSC00191.ppm -quality 100 -define jxl:effort=$e DSC00191_e$e.jxl; done
  0.53
  1.33
  7.71
  $ for m in 0 3 6; do real_time magick DSC00191.ppm -quality 100 -define webp:lossless=true -define webp:method=$m DSC00191_m$m.webp; done
  5.86
  10.41
  46.03
  $ du -k DSC00191* | sort -n
  20068   DSC00191_e9.jxl
  20608   DSC00191_e6.jxl
  21324   DSC00191_m6.webp
  21340   DSC00191_m3.webp
  21772   DSC00191_e3.jxl
  23744   DSC00191.jp2
  23848   DSC00191_s0.avif
  23896   DSC00191_s3.avif
  24212   DSC00191_s6.avif
  24556   DSC00191.png
  26428   DSC00191_m0.webp
  59084   DSC00191.ppm

Not fabulous, really. If you've got a YUV source, everything changes, of course.