Image

Low level utility to perform build-time image transformations for both vector and raster images. Output multiple sizes, save multiple formats, cache remote images locally.

• Uses the sharp image processor.
• eleventy-img on GitHub

You maintain full control of markup. Use with <picture>, <img>, CSS background-image, or others!

• Easily add width and height attributes on <img> elements for proper aspect ratio to reduce layout shift.
• Accepts a variety of image types as input: jpeg, png, webp, gif, tiff, avif, and svg.
  • Does not rely on file extensions (like .png or .jpg) in URLs or local files, which may be missing or inaccurate.
• Output multiple sizes, maintaining the original aspect ratio.
  • Never upscales raster images larger than original size (with the option to upscale SVG input).
• Output multiple formats, supports: jpeg, png, webp, avif +1 Build Cost, and svg (SVG output requires SVG input)
• Fast: de-duplicates image requests with both an in-memory and disk cache. During local development, images are processed on request for even faster build performance.
• Robust: Save remote images locally to prevent broken image URLs (via eleventy-fetch).

Installation

Published as @11ty/eleventy-img on npm.

npm install @11ty/eleventy-img

Usage

This example is the lowest-level use of Eleventy Image and returns a promise. This usage works independent of Eleventy.

import Image from "@11ty/eleventy-img";

let src = "https://images.unsplash.com/photo-1608178398319-48f814d0750c";
let stats = await Image(src, {
	widths: [300],
});

console.log(stats);

const Image = require("@11ty/eleventy-img");

// ESM is required for top level async/await.
(async () => {
	let src = "https://images.unsplash.com/photo-1608178398319-48f814d0750c";
	let stats = await Image(src, {
		widths: [300],
	});

	console.log(stats);
})();

Three things happen here:

1. (Optional) If the first argument is a full URL (not a local file path), we download the remote image and cache it locally using the Fetch plugin. This cached original is then used for the cache duration to avoid a bunch of network requests.
2. Images are then created for each format and width from the input source. In this example, two files are created: ./img/6dfd7ac6-300.webp and ./img/6dfd7ac6-300.jpeg.
3. The promise resolves with a metadata object describing those newly created optimized images.

{
	webp: [
		{
			format: 'webp',
			width: 300,
			height: 300,
			filename: '6dfd7ac6-300.webp',
			outputPath: 'img/6dfd7ac6-300.webp',
			url: '/img/6dfd7ac6-300.webp',
			sourceType: 'image/webp',
			srcset: '/img/6dfd7ac6-300.webp 300w',
			size: 10184
		}
	],
	jpeg: [
		{
			format: 'jpeg',
			width: 300,
			height: 300,
			filename: '6dfd7ac6-300.jpeg',
			outputPath: 'img/6dfd7ac6-300.jpeg',
			url: '/img/6dfd7ac6-300.jpeg',
			sourceType: 'image/jpeg',
			srcset: '/img/6dfd7ac6-300.jpeg 300w',
			size: 15616
		}
	]
}

Output Widths

Controls how many output images will be created for each image format. Aspect ratio is preserved.

• widths: ["auto"] (default, keep original width) "auto".
• widths: [200] (output one 200px width)
• widths: [200, "auto"] (output 200px and original width)

Output Formats

Use almost any combination of these:

• formats: ["webp", "jpeg"] (default)
• formats: ["png"]
• formats: ["auto"] (keep original format) "auto"
• formats: ["svg"] (requires SVG input)
• formats: ["avif"] +1 Build Cost

Output Locations

URL Path

A path-prefix-esque directory for the <img src> attribute. e.g. /img/ for <img src="/img/MY_IMAGE.jpeg">:

• urlPath: "/img/" (default)

Output Directory

Where to write the new images to disk. Project-relative path to the output image directory. Maybe you want to write these to your output directory directly (e.g. ./_site/img/)?

• outputDir: "./img/" (default)

Options for SVG

Skip raster formats for SVG

If using SVG output (the input format is SVG and svg is added to your formats array), we will skip all of the raster formats even if they’re in formats. This may be useful in a CMS-driven workflow when the input could be vector or raster.

• svgShortCircuit: false (default)
• svgShortCircuit: true
• svgShortCircuit: "size" Added in Image v3.1.8

Using svgShortCircuit: "size" means that raster image format entries will only be thrown out if the optimized raster size is larger than the SVG. This helps with large SVG images that compress to smaller raster sizes at smaller widths and will prefer the SVG over raster formats when the SVG file size is smaller.

To use Brotli compressed SVG sizes when making file size comparisons, use the svgCompressionSize: "br" option Added in Image v3.1.8.

Related:

• A New Technique for Image Optimization: SVG Short Circuiting (2023)
• Automatically optimize your images with Eleventy Image and CloudCannon (2023)

Allow SVG to upscale

While we do prevent raster images from upscaling (and filter upscaling widths from the output), you can optionally enable SVG input to upscale to larger sizes when converting to raster format.

• svgAllowUpscale: true (default)
• svgAllowUpscale: false

Use this in your templates

There are four different ways to use Eleventy Image in Eleventy projects:

1. Eleventy Transform (Recommended. Easiest to configure, works with all template types)
2. Asynchronous Shortcode (Nunjucks, Liquid, 11ty.js)
3. WebC Component
4. Synchronous Shortcode (Deprecated)

Eleventy Transform

Pre-release only: v3.0.0-alpha.5 Added in Image v4.0.1This is the easiest method to configure. You add a bit of code to your configuration file and we’ll transform any <img> tags in HTML files that exist in your output folder (probably _site/**/*.html).

Pre-release only: v3.0.0-alpha.7Added in Image v5.0.0During local development (when using --serve), images optimized via transform are not processed at build time and instead are optimized when requested in the browser. Read more about transformOnRequest.

const { eleventyImageTransformPlugin } = require("@11ty/eleventy-img");

module.exports = function (eleventyConfig) {
	eleventyConfig.addPlugin(eleventyImageTransformPlugin, {
		// which file extensions to process
		extensions: "html",

		// Add any other Image utility options here:

		// optional, output image formats
		formats: ["webp", "jpeg"],
		// formats: ["auto"],

		// optional, output image widths
		// widths: ["auto"],

		// optional, attributes assigned on <img> override these values.
		defaultAttributes: {
			loading: "lazy",
			decoding: "async",
		},
	});
};

import { eleventyImageTransformPlugin } from "@11ty/eleventy-img";

export default function (eleventyConfig) {
	eleventyConfig.addPlugin(eleventyImageTransformPlugin, {
		// which file extensions to process
		extensions: "html",

		// Add any other Image utility options here:

		// optional, output image formats
		formats: ["webp", "jpeg"],
		// formats: ["auto"],

		// optional, output image widths
		// widths: ["auto"],

		// optional, attributes assigned on <img> override these values.
		defaultAttributes: {
			loading: "lazy",
			decoding: "async",
		},
	});
}

Relative paths

If you do not specify the urlPath option:

1. Relative image sources (<img src="./possum.png">) will be co-located in your output directory with the template they are used in. Note that if the same source image is used in multiple templates, it will be written to two different locations!
2. Absolute image sources (<img src="/possum.png">) will be normalized relative to your input/content directory and written to your output directory with the default directory (e.g. _site/img/).

Attribute overrides

You can configure individual <img> elements with per-instance overrides:

• <img eleventy:ignore> skips this image.
• <img eleventy:formats="webp"> comma separated string to override the default formats.
• <img eleventy:widths="200,600"> comma separated string to override the default widths.
• <img eleventy:output> overrides the output directory. Similar to urlPath above, absolute paths (e.g. <img eleventy:output="/mydirectory/">) are relative to the Eleventy output directory and relative paths are relative to the template’s URL (e.g. <img eleventy:output="./mydirectory/">).

Nunjucks, Liquid, JavaScript (Asynchronous Shortcodes)

The examples below require an async-friendly shortcodes (works in Nunjucks, Liquid, JavaScript, and WebC).

const Image = require("@11ty/eleventy-img");

// Only one module.exports per configuration file, please!
module.exports = function (eleventyConfig) {
	eleventyConfig.addShortcode("image", async function (src, alt, sizes) {
		let metadata = await Image(src, {
			widths: [300, 600],
			formats: ["avif", "jpeg"],
		});

		let imageAttributes = {
			alt,
			sizes,
			loading: "lazy",
			decoding: "async",
		};

		// You bet we throw an error on a missing alt (alt="" works okay)
		return Image.generateHTML(metadata, imageAttributes);
	});
};

const Image = require("@11ty/eleventy-img");

// Only one module.exports per configuration file, please!
module.exports = function (eleventyConfig) {
	eleventyConfig.addShortcode("image", async function (src, alt, sizes) {
		let metadata = await Image(src, {
			// omitted for brevity
		});

		let imageAttributes = {
			// omitted for brevity
		};

		let options = {
			// HTML attributes added to `<picture>` (left out if <img> is used)
			// Added in v4.0.0
			pictureAttributes: {},

			// Condense HTML output to one line (no new lines)
			// Added in v0.7.3
			whitespaceMode: "inline", // or: "block"
		};

		// You bet we throw an error on a missing alt (alt="" works okay)
		// Note that `options` are *optional*
		return Image.generateHTML(metadata, imageAttributes, options);
	});
};

The addShortcode method is async-friendly in Eleventy 2.0+. Use addAsyncShortcode in older versions of Eleventy. You can also add these shortcodes to individual template engines, if you’d like!

If you want to use Eleventy Image in WebC, take note that it is possible to wire up the method below in WebC. However it is recommended to use the provided <eleventy-image> WebC component instead.

• HTML Tip: Read more about the special (and very useful) loading and decoding HTML attributes.

Now you can use the image shortcode in your templates and the appropriate HTML will be generated for you (based on your specified Image options).

{% image "cat.jpg", "photo of my tabby cat" %}
{% image "cat.jpg", "photo of my tabby cat", "(min-width: 30em) 50vw, 100vw" %}

{% image "cat.jpg", "photo of my tabby cat" %}
{% image "cat.jpg", "photo of my tabby cat", "(min-width: 30em) 50vw, 100vw" %}

module.exports = function() {
	let img1 = await this.image("cat.jpg", "photo of my tabby cat");
	let img2 = await this.image("cat.jpg", "photo of my tabby cat", "(min-width: 30em) 50vw, 100vw");

    return `${img1}

${img2}`;
};

Synchronous Shortcode

const Image = require("@11ty/eleventy-img");
function imageShortcode(src, cls, alt, sizes, widths) {
	let options = {
		widths: widths,
		formats: ["jpeg"],
	};

	// generate images, while this is async we don’t wait
	Image(src, options);

	let imageAttributes = {
		class: cls,
		alt,
		sizes,
		loading: "lazy",
		decoding: "async",
	};
	// get metadata even if the images are not fully generated yet
	let metadata = Image.statsSync(src, options);
	return Image.generateHTML(metadata, imageAttributes);
}

module.exports = function (eleventyConfig) {
	eleventyConfig.addShortcode("myImage", imageShortcode);
};

WebC

Added in Image v3.1.0 Eleventy Image now provides a built-in <eleventy-image> WebC component for use in your Eleventy project.

Using Eleventy Image in WebC offers all the same great benefits you’re used to from Eleventy Image with an intuitive declarative HTML-only developer experience. WebC components work in *.webc files. For similar functionality in other template formats, use the the Liquid/Nunjucks/JavaScript shortcodes above (or even <eleventy-image> with the Render plugin).

First, add the following to your project’s configuration file:

const eleventyWebcPlugin = require("@11ty/eleventy-plugin-webc");
const { eleventyImagePlugin } = require("@11ty/eleventy-img");

// Only one module.exports per configuration file, please!
module.exports = function (eleventyConfig) {
	// WebC
	eleventyConfig.addPlugin(eleventyWebcPlugin, {
		components: [
			// …
			// Add as a global WebC component
			"npm:@11ty/eleventy-img/*.webc",
		],
	});

	// Image plugin
	eleventyConfig.addPlugin(eleventyImagePlugin, {
		// Set global default options
		formats: ["webp", "jpeg"],
		urlPath: "/img/",

		// Notably `outputDir` is resolved automatically
		// to the project output directory

		defaultAttributes: {
			loading: "lazy",
			decoding: "async",
		},
	});
};

Pre-release only: v3.0.0-alpha.7Added in Image v5.0.0During local development (when using --serve), <eleventy-image> images are not processed at build time and instead are optimized when requested in the browser. Read more about transformOnRequest.

• HTML Tip: Read more about the special (and very useful) loading and decoding HTML attributes.

Now you can use the <eleventy-image> WebC component in your templates.

<img webc:is="eleventy-image" src="cat.jpg" alt="photo of my tabby cat" />
<eleventy-image src="cat.jpg" alt="photo of my tabby cat"></eleventy-image>

<!-- Specify widths: -->
<img
	webc:is="eleventy-image"
	width="100, 200"
	src="cat.jpg"
	alt="photo of my tabby cat"
/>
<img
	webc:is="eleventy-image"
	:width="[100, 200]"
	src="cat.jpg"
	alt="photo of my tabby cat"
/>

<!-- Specify formats (overriding defaults set via the configuration) -->
<img
	webc:is="eleventy-image"
	formats="avif, png"
	src="cat.jpg"
	alt="photo of my tabby cat"
/>
<img
	webc:is="eleventy-image"
	:formats="['avif', 'png']"
	src="cat.jpg"
	alt="photo of my tabby cat"
/>

<!-- Change the url path or output dir (overriding defaults set via the configuration above) -->
<img
	webc:is="eleventy-image"
	url-path="/some-dir/"
	output-dir="_site/some-dir/"
	src="cat.jpg"
	alt="photo of my tabby cat"
/>

Build Cost 🧰

Image optimization is likely one of the costlier pieces of your Eleventy build. The total build cost of this utility is dependent on a few things:

1. Number of unique images optimized (not number of pages)
2. Number of widths you generate for each source image.
3. Number of formats you generate for each source image.
   • avif is more costly than other image formats. +1 Build Cost
4. File size of images being optimized (larger source images are more expensive).
5. Optimizing a lot of remote images (image content must be fetched from a remote server and is subsequently cached via eleventy-fetch).

Optimize Images on Request

Pre-release only: v3.0.0-alpha.7Added in Image v5.0.0When using the transform method or the WebC component, image processing is removed from the build for extra performance. Instead, they are processed when requested by the browser using a special middleware built-in to the Eleventy Dev Server. This is enabled or disabled using the transformOnRequest option.

• transformOnRequest: false (default)
• transformOnRequest: process.env.ELEVENTY_RUN_MODE === "serve" (default for Transform method and WebC)

Optimize On Request with Shortcodes

Pre-release only: v3.0.0-alpha.7Added in Image v5.0.0You can use this with the Eleventy Shortcode directly too, with a little bit more configuration:

const Image = require("@11ty/eleventy-img");
const { eleventyImageOnRequestDuringServePlugin } = Image;

// Only one module.exports per configuration file, please!
module.exports = function (eleventyConfig) {
	eleventyConfig.addShortcode("image", async function (src, alt) {
		let metadata = await Image(src, {
			transformOnRequest: process.env.ELEVENTY_RUN_MODE === "serve"
		});

		// You bet we throw an error on a missing alt (alt="" works okay)
		return Image.generateHTML(metadata, imageAttributes);
	});

	// Add the dev server middleware manually
	eleventyConfig.addPlugin(eleventyImageOnRequestDuringServePlugin);
};

In-Memory Cache

To prevent duplicate work and improve build performance, repeated calls to the same source image (remote or local) with the same options will return a cached results object. If a request in-progress, the pending promise will be returned. This in-memory cache is maintained across builds in watch/serve mode. If you quit Eleventy, the in-memory cache will be lost.

Images will be regenerated (and the cache ignored) if:

• The source image file size changes (on local image files)
• The cache asset duration expires (for remote images).

You can disable this behavior by using the useCache boolean option:

• useCache: true (default)
• useCache: false to bypass the cache and generate a new image every time.

Examples

const Image = require("@11ty/eleventy-img");

(async () => {
	let stats1 = Image("./test/bio-2017.jpg");
	let stats2 = Image("./test/bio-2017.jpg");

	console.assert(stats1 === stats2, "The same promise");
})();

const Image = require("@11ty/eleventy-img");

(async () => {
	let stats1 = Image("./test/bio-2017.jpg");
	let stats2 = Image("./test/bio-2017.jpg", { widths: [300] });

	console.assert(stats1 !== stats2, "A different promise");
})();

Disk Cache

Added in Image v1.0.0 Eleventy will skip processing files that are unchanged and already exist in the output directory. This requires the built-in hashing algorithm and is not yet supported with custom filenames. More background at Issue #51.

You can use this to speed up builds on your build server.

Advanced Usage

Fix Orientation

Added in Image v4.0.0Rotates the image to enforce the correct orientation set in EXIF metadata.

• fixOrientation: false (default)
• fixOrientation: true

Custom Filenames

Don’t like those hash ids? Make your own!

{
	// Define custom filenames for generated images
	filenameFormat: function (id, src, width, format, options) {
		// id: hash of the original image
		// src: original image path
		// width: current width in px
		// format: current file format
		// options: set of options passed to the Image call

		return `${id}-${width}.${format}`;
	}
}

const path = require("path");
const Image = require("@11ty/eleventy-img");

await Image("./test/bio-2017.jpg", {
	widths: [300],
	formats: ["auto"],
	filenameFormat: function (id, src, width, format, options) {
		const extension = path.extname(src);
		const name = path.basename(src, extension);

		return `${name}-${width}w.${format}`;
	},
});

// Writes: "test/img/bio-2017-300w.jpeg"

Dry-Run

If you want to try the utility out and not write any files (useful for testing), use the dryRun option.

• dryRun: false (default)
• dryRun: true

Make your own Markup

If you have an advanced use case and don’t want to use our methods to generate the image markup, you can do it yourself!

const Image = require("@11ty/eleventy-img");

// Only one module.exports per configuration file, please!
module.exports = function (eleventyConfig) {
	eleventyConfig.addShortcode("image", async function (src, alt) {
		if (alt === undefined) {
			// You bet we throw an error on missing alt (alt="" works okay)
			throw new Error(`Missing \`alt\` on myImage from: ${src}`);
		}

		let metadata = await Image(src, {
			widths: [600],
			formats: ["jpeg"],
		});

		let data = metadata.jpeg[metadata.jpeg.length - 1];
		return `<img src="${data.url}" width="${data.width}" height="${data.height}" alt="${alt}" loading="lazy" decoding="async">`;
	});
};

const Image = require("@11ty/eleventy-img");

// Only one module.exports per configuration file, please!
module.exports = function (eleventyConfig) {
	eleventyConfig.addShortcode(
		"image",
		async function (src, alt, sizes = "100vw") {
			if (alt === undefined) {
				// You bet we throw an error on missing alt (alt="" works okay)
				throw new Error(`Missing \`alt\` on responsiveimage from: ${src}`);
			}

			let metadata = await Image(src, {
				widths: [300, 600],
				formats: ["webp", "jpeg"],
			});

			let lowsrc = metadata.jpeg[0];
			let highsrc = metadata.jpeg[metadata.jpeg.length - 1];

			return `<picture>
			${Object.values(metadata)
				.map((imageFormat) => {
					return `  <source type="${
						imageFormat[0].sourceType
					}" srcset="${imageFormat
						.map((entry) => entry.srcset)
						.join(", ")}" sizes="${sizes}">`;
				})
				.join("\n")}
				<img
					src="${lowsrc.url}"
					width="${highsrc.width}"
					height="${highsrc.height}"
					alt="${alt}"
					loading="lazy"
					decoding="async">
			</picture>`;
		}
	);
};

Process images as a Custom Template

Use Eleventy’s Custom Template Language feature to process images. This one is not yet available on the docs: do you want to contribute it?

Process images as Data Files

Added in v2.0.0 Nontraditional use case. Eleventy’s Custom Data File Formats features an example of processing Images as data files to feed EXIF data into the Data Cascade. You can use the same feature to add the metadata stats returned from the Image utility directly to the Data Cascade for use in your templates.

• Benefits:
  • Processing happens in the data cascade so this works in any template language.
  • Images stored in the global data folder will be processed and available to all templates
• Drawbacks:
  • You can’t customize the Image options (e.g. widths or formats) from the template code. It is set globally in the config.
• Both a benefit and a drawback:
  • Beholden to Eleventy’s Data Cascade file name conventions when using with template/directory data files.

const Image = require("@11ty/eleventy-img");
const path = require("path");

module.exports = function (eleventyConfig) {
	eleventyConfig.addDataExtension("png,jpeg", {
		read: false, // Don’t read the input file, argument is now a file path
		parser: async (imagePath) => {
			let stats = await Image(imagePath, {
				widths: ["auto"],
				formats: ["avif", "webp", "jpeg"],
				outputDir: path.join(eleventyConfig.dir.output, "img", "built"),
			});

			return {
				image: {
					stats,
				},
			};
		},
	});

	// This works sync or async: images were processed ahead of time in the data cascade
	eleventyConfig.addShortcode("dataCascadeImage", (stats, alt, sizes) => {
		let imageAttributes = {
			alt,
			sizes,
			loading: "lazy",
			decoding: "async",
		};
		return Image.generateHTML(stats, imageAttributes);
	});
};

{% dataCascadeImage image.stats, "My alt text" %}

Change Global Plugin Concurrency

const Image = require("@11ty/eleventy-img");
Image.concurrency = 4; // default is 10

Advanced control of Sharp image processor

Extra options to pass to the Sharp constructor or the Sharp image format converter for webp, png, jpeg, or avif.

• sharpOptions: {}
• sharpWebpOptions: {}
• sharpPngOptions: {}
• sharpJpegOptions: {}
• sharpAvifOptions: {}

Output Animated GIF or WebP

Added in Image v1.1.0 To process and output animated gif or webp images, use the animated option for the Sharp constructor.

const Image = require("@11ty/eleventy-img");

await Image("./test/bio-2017.jpg", {
	formats: ["webp", "gif"],

	sharpOptions: {
		animated: true,
	},
});

Change the default Hash length

Added in v1.0.0 You can customize the length of the default filename format hash by using the hashLength property.

const Image = require("@11ty/eleventy-img");

await Image("./test/bio-2017.jpg", {
	hashLength: 8, // careful, don’t make it _too_ short!
});

Advanced Caching Options for Remote Images

For any full URL first argument to this plugin, the full-size remote image will be downloaded and cached locally. See all relevant eleventy-fetch options.

{
	cacheOptions: {
		// if a remote image URL, this is the amount of time before it fetches a fresh copy
		duration: "1d",

		// project-relative path to the cache directory
		directory: ".cache",

		removeUrlQueryParams: false,
	},
}

When caching remote images, you may want to check the processed image output into your git (et al) repository to avoid refetches in the future. If remote images are not checked in, they may be refetched every time on your CI server unless you preserve the .cache folder between builds.

Using a Hosted Image Service

Custom URLs

Want to use a hosted image service instead? You can override the entire URL. Takes precedence over filenameFormat option. Useful with statsSync or statsByDimensionsSync.

The metadata object returned will not include filename or outputPath properties.

{
	urlFormat: function ({
		hash, // not included for `statsOnly` images
		src,
		width,
		format,
	}) {
		return `https://example.com/${encodeURIComponent(src)}/${width}/${format}/`;
	}
}

• Example on 11ty-website

Stats Only

Added in Image v1.1.0 Skips all image processing to return metadata. Doesn’t read files, doesn’t write files. Use this as an alternative to the separate statsSync* functions—this will use in-memory cache and de-duplicate requests.

• statsOnly: false (default)
• statsOnly: true

For versions prior to Image 5.0, you need to supply the dimensions when using statsOnly via remoteImageMetadata:

{
	statsOnly: true,
	// Not required in Image 5.0+
	remoteImageMetadata: {
		width,
		height,
		format, // optional
	}
}

From the Community

Using Eleventy’s official image plugin

Optimizing Images with the 11ty Image Plugin

Don’t Shut Down Your Business! Instead Use Eleventy Image

+ Add yours!

×80 resources courtesy of 11tybundle.dev curated by Bob Monsour

• 11ty : how to use the image plugin to generate responsive images for CSS — Phil Rentier Digital (2024)
• Building a Web Version of Your Mastodon Archive with Eleventy — Raymond Camden (2024)
• Adding a Photo Stream to an Eleventy Site — nonnullish (2024)
• Twenty year celebration: Site update number three — Peter Sefton (2024)
• Upgrading to Eleventy v3 — Alex Zappa (2024)

Other pages in Official Plugins:

• Image
• Fetch
• <is-land>
• Render
• Internationalization (i18n)
• RSS
• Upgrade Helper
• Syntax Highlighting
• InputPath to URL
• Navigation
• HTML <base>
• Directory Output
• Inclusive Language
• Edge
• Serverless