SVGZ and lossy compression

original file: lab.png (300.14 KB): svgz container and lossy compression
original WebP (cwebp default) pingo -svgz=16
lab - PNG lab - cwebp lab - svgz lossy
300.14 KB 66.34 KB (0.16s) 39.06 KB (0.13s)
dssim - butteraugli 0.00100984 - 3.728334 0.00082322 - 3.416768

color quantization, reduce the number of colors (PNG)

original file: palette-colours.png (71.03 KB): PNG color quantization
original pingo -pngcolor=100
palette colours - original palette colours - pngfilter 100
71.03 KB — 15359 colors 60.21 KB (0.11s) — 9657 colors
dssim - butteraugli 0.00003171 — 0.564144

JPG subsampling (chroma subsampling)

original file: rvb.png chroma subsampling
-jpgsample=0 (default) -jpgsample=2
rvb - sample 0 rvb - sample 2
47.44 KB (quality 100) 33.38 KB (quality 100)
1x1,1x1,1x1 (4:4:4) 2x2,1x1,1x1 (4:2:0)

WebP paletted encoding

original file: firefox.png (22.01 KB): paletted WebP (lossy)
original pingo -webp-palette=30
firefox - original firefox - webp palette 30
22.01 KB 8.06 KB (0.09s)
dssim - butteraugli 0.00001264 - 1.556444

convert JPG to PNG (with filter)

original file: image-optimisation.jpg (254.14 KB): JPG to PNG conversion with more colors
original pingo -pngconvert=8 -pngpalette=100
hand - original hand - original
254.14 KB 63.84 KB (0.78s)

how to optimize PNG losslessly for web

original file: rose.png (70 KB): remove non-rendered image data
original file pingo -s1
rose rose - pingo
70 KB (3.49s) 31.95 KB (0.13s) - PNG

WebP alternative near-lossless image compression (filter)

original file: orange.png (222.65 KB): alternative near-lossless WebP (lossy)
original pingo -webp-filter=40
orange - original orange - webp near lossless 50
222.65 KB 86.25 KB (0.32s)
dssim - butteraugli 0.00089928 - 2.105718

convert PNG to JPG

original file: fruits-iccp-noalpha.png (385.09 KB): PNG to JPG (conversion to sRGB colorspace)
original pingo -jpgconvert
fruits - sRGB PhotoShop fruits - sRGB pingo auto
385.09 KB 67.83 KB (0.12s) - JPG
iCCP chunk (colors profile) converted to sRGB

set a specific quality factor for JPG

original file: bees.png (170.34 KB): set JPG quality
original pingo -jpgquality=90
bees - original bees - jpgquality90
170.34 KB 34.80 KB (0.09s)

WebP alternative near-lossless image compression (color)

original file: mac.png (222.65 KB): alternative near-lossless WebP (lossy)
original pingo -webp-color=60
mac - original mac - webp near lossless color 60
222.65 KB 106.80 KB (0.31s)
dssim - butteraugli 0.00025188 - 1.374627