FLIF is a lossless format, but that doesn't mean it cannot also be used in a lossy way.
Here is a case study to let you judge for yourself. You can click on the small crops to get the full image.
There is also an interactive image format comparison page
where you can visually compare several image formats, including lossy encoded FLIF.
Note however that FLIF is a lossless format, and any compression artifact is only caused by the optional lossy preprocessing step.
This means that if you see an annoying artifact in some specific part of the image, you can easily eliminate it by telling the lossy
preprocessor to be less lossy on that particular part of the image (you can use the encode option --adaptive for this).
In other image formats, this is usually also possible, but harder to do and with more restrictions.
| Original (lossless) 1,688,504 byte PNG 1,321,602 byte FLIF 1,398,900 byte WebP PSNR: inf DSSIM: 0 |
Lossy FLIF 969,683 bytes PSNR: 52.1842 DSSIM: 0.000109 |
JPEG (quality 99) 1,100,684 bytes PSNR: 48.0707 DSSIM: 0.000182 |
WebP (near-lossless) 1,021,038 bytes PSNR: 38.2652 DSSIM: 0.001794 |
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| Original (lossless) PSNR: inf DSSIM: 0 |
Lossy FLIF 541,226 bytes PSNR: 45.5374 DSSIM: 0.000411 |
JPEG (quality 96) 598,955 bytes PSNR: 42.4322 DSSIM: 0.000456 |
WebP (quality 100) 564,464 bytes PSNR: 38.6303 DSSIM: 0.000600 |
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| Original (lossless) PSNR: inf DSSIM: 0 |
Lossy FLIF 324,769 bytes PSNR: 41.6185 DSSIM: 0.001096 |
JPEG (quality 90) 345,714 bytes PSNR: 38.2847 DSSIM: 0.001040 |
WebP (quality 95) 328,550 bytes PSNR: 38.0839 DSSIM: 0.001048 |
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| Original (lossless) PSNR: inf DSSIM: 0 |
Lossy FLIF 151,646 bytes PSNR: 36.6284 DSSIM: 0.003890 |
JPEG (quality 80) 164,136 bytes PSNR: 33.975 DSSIM: 0.002876 |
WebP (quality 85) 156,408 bytes PSNR: 36.0936 DSSIM: 0.002792 |
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| Original (lossless) PSNR: inf DSSIM: 0 |
Lossy FLIF 52,981 bytes PSNR: 30.6999 DSSIM: 0.014995 |
JPEG (quality 25) 54,810 bytes PSNR: 29.8108 DSSIM: 0.015136 |
WebP (quality 34) 54,556 bytes PSNR: 31.6246 DSSIM: 0.012044 |
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| Original (lossless) PSNR: inf DSSIM: 0 |
Lossy FLIF 18,822 bytes PSNR: 26.937 DSSIM: 0.047244 |
JPEG (quality 7) 19,627 bytes PSNR: 25.9092 DSSIM: 0.073680 |
WebP (quality 2) 18,822 bytes PSNR: 27.4588 DSSIM: 0.041058 |
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