eleventy.config.images.js

import path from 'node:path'
import eleventyImage from '@11ty/eleventy-img'

export default function imagesConfig(eleventyConfig) {
  function relativeToInputPath(inputPath, relativeFilePath) {
    let split = inputPath.split('/')
    split.pop()

    return path.resolve(split.join(path.sep), relativeFilePath)
  }

  // Eleventy Image shortcode
  // https://www.11ty.dev/docs/plugins/image/
  eleventyConfig.addAsyncShortcode(
    'image',
    async function imageShortcode(src, alt, widths, sizes) {
      // Full list of formats here: https://www.11ty.dev/docs/plugins/image/#output-formats
      // Warning: Avif can be resource-intensive so take care!
      let formats = ['avif', 'webp', 'auto']
      let file = relativeToInputPath(this.page.inputPath, src)
      let metadata = await eleventyImage(file, {
        widths: widths || ['auto'],
        formats,
        outputDir: path.join(eleventyConfig.dir.output, 'img') // Advanced usage note: `eleventyConfig.dir` works here because we’re using addPlugin.
      })

      // TODO loading=eager and fetchpriority=high
      let imageAttributes = {
        alt,
        sizes,
        loading: 'lazy',
        decoding: 'async'
      }
      return eleventyImage.generateHTML(metadata, imageAttributes)
    }
  )
}