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

Features Jump to heading #

You maintain full control of the HTML. Use with <picture> or <img> or CSS background-image, or others! Works great to add width and height to your images!

• Accepts a variety of image types as input: jpeg, png, webp, gif, tiff, avif, and svg.
• Output multiple sizes, keeping 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, and svg (requires SVG input)

Even more features Jump to heading #

• Easily add width and height attributes on <img> elements for proper aspect ratio mapping.
• Does not require or rely on file extensions (like .png or .jpg) in URLs or local files, which may be missing or inaccurate.
• Save remote images locally to prevent broken image URLs (using eleventy-fetch).
• Fast: de-duplicates image requests and uses both an in-memory and disk cache.

Installation Jump to heading #

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

npm install @11ty/eleventy-img

Usage Jump to heading #

This utility returns a Promise and works best in async friendly functions, filters, shortcodes. It can also work in synchronous environments (Synchronous Usage).

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

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

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

Three things happen here:

1. 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. From that cached full-size original, images are created for each format and width, in this case: ./img/6dfd7ac6-300.webp and ./img/6dfd7ac6-300.jpeg.
3. A metadata object is returned, describing those new 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
		}
	]
}

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

(async () => {
	let stats = await Image("…", {
		// Array of integers or "auto"
		widths: ["auto"],

		// Array of file format extensions or "auto"
		formats: ["webp", "jpeg"],

		// the URLs in markup are prefixed with this
		urlPath: "/img/",

		// the images are written here
		outputDir: "./img/",

		// skip raster formats if SVG available
		svgShortCircuit: false,

		// SVG file sizes can report the compressed size
		svgCompressionSize: "",

		// allow svg to upscale beyond supplied dimensions?
		svgAllowUpscale: true,

		// the file name hash length
		hashLength: 10,

		// Custom file name callback (see below)
		filenameFormat: function() {},

		// Advanced options passed to eleventy-fetch
		cacheOptions: {},

		// Advanced options passed to sharp
		sharpOptions: {},
		sharpWebpOptions: {},
		sharpPngOptions: {},
		sharpJpegOptions: {},
		sharpAvifOptions: {},

		// Custom full URLs (use with hosted services, see below)
		urlFormat: function() {},
	});
})();

Output Widths Jump to heading #

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 Jump to heading #

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"]

Output Locations Jump to heading #

URL Path Jump to heading #

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 Jump to heading #

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 Jump to heading #

Skip raster formats for SVG Jump to heading #

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 Jump to heading #

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

Custom Filenames Jump to heading #

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"

Use this in your templates Jump to heading #

WebC Jump to heading #

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.

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"
		}
	});
};

• 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">

Nunjucks, Liquid, JavaScript (Asynchronous Shortcodes) Jump to heading #

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

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.

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);
	});
};

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!

• 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 Jump to heading #

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.addNunjucksShortcode("myImage", imageShortcode);
}

Make your own Markup Jump to heading #

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 Jump to heading #

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 Jump to heading #

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" %}

Advanced Usage Jump to heading #

Caching Jump to heading #

In-Memory Cache Jump to heading #

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 Jump to heading #

Added in Image 1.0.0 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.

New tip: Re-use and persist the disk cache across Netlify builds

Dry-Run Jump to heading #

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

• dryRun: false (default)
• dryRun: true

Change Global Plugin Concurrency Jump to heading #

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

Advanced control of Sharp image processor Jump to heading #

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 Jump to heading #

Added in Image 1.1.0 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 Jump to heading #

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 Jump to heading #

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 Jump to heading #

Custom URLs Jump to heading #

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

When you use this, returned data will not include filename or outputPath.

{
	urlFormat: function ({
		hash, // not included for `statsOnly` images
		src,
		width,
		format,
	}) {
		return `https://sample-image-service.11ty.dev/${encodeURIComponent(src)}/${width}/${format}/`;
	}
}

• Example on 11ty-website

Stats Only Jump to heading #

Added in Image 1.1.0 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

With remotely hosted images, you may also need to supply the dimensions when using statsOnly:

{
	statsOnly: true,
	remoteImageMetadata: {
		width,
		height,
		format, // optional
	}
}

From the Community Jump to heading #

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!

×49 resources courtesy of 11tybundle.dev curated by Bob Monsour

• VSCode Pasting 11ty Images — Jeff Sheets (2023)
• A new technique for image optimization: SVG short circuiting — Zach Leatherman (2023)
• Automatically optimize your images with Eleventy Image and CloudCannon — Zach Leatherman (2023)
• Building a photography website — Darek Kay (2023)
• Making a lighthouse-fast website with a static site generator like 11ty — Piotr Maliński (2023)

Other pages in Plugins:

• Edge
• Serverless
• Image
• Fetch
• Partial Hydration <is-land>
• Render
• Internationalization (i18n)
• RSS
• Syntax Highlighting
• Navigation
• HTML <base>
• Directory Output
• Inclusive Language