imageFormatFallback

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This repo is archived

This repo has been stale for years, and there are alternatives.

Alternatives include

• HTML Picture-Tag
• CSS @media / @supports
• check request headers for support (with Htaccess or PHP)
• As of 2026, WEBP is pretty much universally supported anyway. Exotic file formats are exotic anyway and shouldn't be used. In cases where PNGs are preferred, check out Oxipng

* As of 2026, I'm currently mirroring Repos from GitHub to GitLab bidirectionally. Target platform might change later.
GitLab: https://gitlab.com/Maingron/imageFormatFallback-js
GitHub: https://github.com/Maingron/imageFormatFallback.js

News - Read first: #13 (Cancel development because of alternatives)

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How to use

1. Load images onto the server - In this example we have image.webp; image.xjr and image.jpg
2. Go into the HTML and add the format Attribute to your <img>-Tag: <img src="images/image.webp" formats="webp,xjr,jpg" alt="image">
3. Publish.

Configuration options

• fallbackPrefix: If all your fallback images should have a prefix, you can set it here. Example: "fallback_"
• fallbackAttributeName: If you want a different attribute than formats="", you can set it here

Supported image formats

• .avif
• .bmp
• .gif
• .heic
• .ico
• .jpg
• .jxr
• .png
• .tga
• .tiff
• .webp

Tested working browsers

• Firefox 8 and later
• Google Chrome 9 and later
• Internet Explorer 9 and later
• Safari 3 and later
• Opera 12 and later
• Other Browsers:
  • Nintendo 3DS Browser
  • Nintendo Switch Browser
  • Playstation 3 Browser