Lossless picture compression comparison
A quick and dirty test regarding which lossless picture compression format should I use for Web or Archiving.
During testing, Gimp PNG is used as a baseline, and the following commands were used to try and achieve better compression:
#PNG (Optimized)
zopflipng -y -m <IN> <OUT>
#JPEG XL (Lossless)
cjxl --num_threads=8 -v -q 100 -e 9 --brotli_effort=11 <IN> <OUT>
#WebP (Lossless)
convert <IN> -define webp:lossless=true -define webp:method=6 <OUT>
#AVIF (Lossless)
avifenc --jobs 8 --lossless --speed 0 --codec aom <IN> <OUT>
Picture
A picture of a few objects on a table, an RNG I made some time ago. This picture is something PNG nor any lossless picture format should not be that good at.
Results
| Format | Time | Size | Ratio |
|---|---|---|---|
| PNG (Gimp) | 1s |
476K |
100.0% |
| PNG (Zopfli) | 21s |
463K |
97.3% |
| AVIF (aom) | 18s |
402K |
84.5% |
| WebP | 1s |
361K |
75.8% |
| JPEG XL | 25s |
324K |
68.1% |
Screenshot
A Windows XP dialog screenshot, large areas of the same color. Something PNG is good at, as should any lossless format.
Results
| Format | Time | Size | Ratio |
|---|---|---|---|
| PNG (Gimp) | 1s |
6.4K |
100.0% |
| AVIF (aom) | 11s |
11.9K |
187.2% |
| PNG (Zopfli) | 19s |
5.5K |
85.7% |
| WebP | 0s |
4.9K |
76.9% |
| JPEG XL | 2s |
3.6K |
55.1% |
Conclusion
WebP for web, JPEG XL for archiving. AVIF is a clear loser for lossless compression being not the best when improving on PNG, too slow, and sometimes having significantly worse compression than even un optimized PNG.