demo · runs in this browser · nothing is uploaded

Demo.

Drop an image, or try a sample. It is encoded and scored here, and the numbers are browser estimates. The CLI measures the live page.

Drop an image here.

JPEG, PNG, WebP or AVIF. Up to 4000 px on the long side. Or click to choose a file.

Samples:

1. Display width

The image's width on the page, at each viewport. The demo encodes at the widths these rows need.

or paste a sizes value

viewport	css px	dpr	needed px
iphone-se	375	2x	750
iphone-15	390	3x	1170
pixel-7	412	2.625x	1082
iphone-15-pro-max	430	3x	1290
desktop	1440	2x	2880
desktop-1280	1280	1x	1280

Needed px = CSS width x dpr, rounded up. Viewports and dpr are the CLI's six.

2. Run

skip AVIF (slow on phones)

Scoring: SSIMULACRA2 from ImgTune's crate, built for the web. Codecs: jSquash (MozJPEG, libwebp, libavif). Each codec is downloaded the first time you drop a file. Images up to 4000 px on the long side are decoded here, and the page keeps them only while it is open.