If you are pulling your Eleventy content from a cloud-based CMS or third-party API, then chances are high that any images referenced in the content will also be hosted in cloud storage. However, Harry Roberts has suggested that it is usually more performant to self-host your static assets rather than host them on a CDN (source).

This plugin is a post-processor that looks for image paths within your generated site, pulls down a uniquely-hashed local copy of each remote image and updates the filepaths in markup - That way you can be confident that your site's images will still be working, even if your CMS or cloud storage goes down.

From your project directory run:

npm install eleventy-plugin-local-images --save-dev

Once the package has installed, open up your .eleventy.js file.

Step 1: Require the plugin

const localImages = require('eleventy-plugin-local-images');

Step 2: Configure and add the plugin:

module.exports = function(eleventyConfig) {
  eleventyConfig.addPlugin(localImages, {
    distPath: '_site',
    assetPath: '/assets/img',
    selector: 'img',
    verbose: false
  });
};

Currently, as all of the image checks are carried out asynchronously, if multiple <img> tags exist with the same src attribute, the plugin will attempt to download the file for each instance of the path.

This isn't as efficient as it should be, however the plugin will always save the file with the same hashed filename, so it will at least not result in duplicated files on your local storage.

I'm really happy to consider any contributions to this plugin. Before you make any changes, please read the contribution guide.