More AVIF and WebP lossy tests

Here we have more lossy tests of AVIF and WebP comparing to JPEG or PNG, but with the much smaller resolution and very close file size for testing the real-life usages. By using the <picture> tag, the priority is AVIF, WebP, and JPEG/PNG so all browsers can display.

	<source srcset="photo.avif" type="image/avif">
	<source srcset="photo.webp" type="image/webp">
	<img src="photo.jpg" alt="">


These tools make sure that the results would be fair and reliable.


  • AVIF: Default (–min Q 1, –maxQ 10; added –minalpha Q 1, –maxalpha Q 10 for images without backgrounds)
  • WebP: 92
  • JPEG: 55
  • PNG: 40

AVIF is the base for the file size because of its superiority. PNG is not lossy, but dithering should be more defined when the colours are further reduced below 256 for the much smaller file size.


All images are safe for work. Files of Bustycat are shrunk to 1600 × 1200 pixels (0.11), while files of 🔞Reconquest and 🔞Reconquest at Night are shrunk to 1400 × 1400 pixels (0.16).

Normal images

AVIF 191 KB; WebP 192 KB; JPEG 196 KB
AVIF 247 KB; WebP 257 KB; JPEG 251 KB
AVIF 249 KB; WebP 259 KB; JPEG 253 KB
AVIF 129 KB; WebP 136 KB; JPEG 156 KB
AVIF 131 KB; WebP 138 KB; JPEG 158 KB

Images with the alpha channel

AVIF 117 KB; WebP 121 KB; PNG 178 KB
AVIF 143 KB; WebP 155 KB; PNG 232 KB
AVIF 149 KB; WebP 160 KB; PNG 248 KB


AVIF images with even the default quality still look decent, but the file size is not large comparing to other image formats. WebP, however, is not very superior to MozJPEG because the results are significantly closer. For lossy images with the alpha channel, both of AVIF and WebP are better regarding to the quality and file size, as PNG is always lossless and JPEG does not support the alpha channel.

Some people said the quality of most of images on the internet are higher than what people need, but the reality is they look bad instead. The main reason is the outdated JPEG format, but lacking optimisation like MozJPEG (ImageOptim uses) results in larger files too. Before AVIF and WebP become more widespread, optimisation for JPEG and PNG remains very important for saving data traffic.

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