Image file formats

Modern image formats, for my reference, with particular attention to the ones that are good for the web.

Note, that despite the apparently benign nature of tacking a representation of pixels from a file and putting it on a screen, image libraries have a long history of security bugs, including disastrous ones.


WebP image format is supported on most modern browsers. Notably, things that are not browsers are a bit crap at WebP, so chat programs and feed readers fail to create thumbnails of websites using WebP. Probably they will only support GIF89a until the end of time. That is why sometime the page previews for this site look a bit crap; I use WebP quite a lot.

Famous webP security vulnerability: CVE-2023-4863; tl;dr all software using WebP before 2023-09-14 was vulnerable to remote code execution.


The most futuristic image format with reasonable support, i.e. 70% of browsers and rising. It will even work in Microsoft Edge in the next version, supposedly. Like WebP, many non-browser apps are no good at AVIF, so some websites fail to render AVIF thumbnails; but that won’t stop me from using it, because it does amazingly well at squeezing down high-resolution images. I’m not being paid to work around their deficiencies.

Fringe options


Previewing in macos

See macos image preview.

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