5 ms·

Few benchmarks using Cmd+4'd of my working Firefox window. Tested with: pngnq -n 256 image.png optipng -o7 image.png advpng -z4 image.png pngout image

by sirn 16y ago

Few benchmarks using Cmd+4'd of my working Firefox window. Tested with: pngnq -n 256 image.png optipng -o7 image.png advpng -z4 image.png pngout image.png Results: 312822 test-firefox.png 181394 test-firefox-advpng.png 199005 test-firefox-optipng.png 235635 test-firefox-pngout.png 181394 test-firefox-full.png 79793 test-firefox-nq8.png 74917 test-firefox-nq8-advpng.png 79683 test-firefox-nq8-optipng.png 76017 test-firefox-nq8-pngout.png 74917 test-firefox-nq8-full.png Samples: Original http://gridth.s3.amazonaws.com/test-firefox.png Quantized http://gridth.s3.amazonaws.com/test-firefox-nq8.png The result file size is impressive, but the image quality is noticeably worse. I'm not sure if I want to use color quantization with PNG though. After all, if I want a lossy compression, I'd use JPEG.

Rauchg 16y ago
I think it's a fantastic result. Very useful for including screenshots in blog posts without sacrificing too much quality, but clearly decreasing size.
gus_massa 16y ago
Clickable links: Original: http://gridth.s3.amazonaws.com/test-firefox.png http://gridth.s3.amazonaws.com/test-firefox.png Quantized: http://gridth.s3.amazonaws.com/test-firefox-nq8.png http://gridth.s3.amazonaws.com/test-firefox-nq8.png
- MikeCapone 16y ago
  Only place it's noticeable is the header of the page. I wonder if it's the only place where it save bits, or if it saves some in the rest too. If it does, that seems like the kind of graphic you'd want to use it with.
For_Iconoclasm 16y ago
This is exactly what I don't understand about the existence of this program. I don't know much about compression algorithms, but this is definitely lossy compression. I don't know why somebody would want to use it on their lossless PNGs when JPG already exists.
- ugh 16y ago
  You want to use it when you don’t want any ugly JPG compression artifacts to show up. PNG and JPG produce different compression artifacts, depending on what you are compressing either one could look better.
- chipsy 16y ago
  PNG8 allows you to use alpha in palettized form. Images you want to use in a "composite" context(icons, buttons, sprites, etc.) really need alpha to look great, but you don't usually need the full color gamut for them either.

by sirn 16y ago

Rauchg 16y ago

I think it's a fantastic result. Very useful for including screenshots in blog posts without sacrificing too much quality, but clearly decreasing size.

gus_massa 16y ago

Clickable links: Original: http://gridth.s3.amazonaws.com/test-firefox.png http://gridth.s3.amazonaws.com/test-firefox.png Quantized: http://gridth.s3.amazonaws.com/test-firefox-nq8.png http://gridth.s3.amazonaws.com/test-firefox-nq8.png

MikeCapone 16y ago
Only place it's noticeable is the header of the page. I wonder if it's the only place where it save bits, or if it saves some in the rest too. If it does, that seems like the kind of graphic you'd want to use it with.

For_Iconoclasm 16y ago

This is exactly what I don't understand about the existence of this program. I don't know much about compression algorithms, but this is definitely lossy compression. I don't know why somebody would want to use it on their lossless PNGs when JPG already exists.

ugh 16y ago
You want to use it when you don’t want any ugly JPG compression artifacts to show up. PNG and JPG produce different compression artifacts, depending on what you are compressing either one could look better.
chipsy 16y ago
PNG8 allows you to use alpha in palettized form. Images you want to use in a "composite" context(icons, buttons, sprites, etc.) really need alpha to look great, but you don't usually need the full color gamut for them either.