Images

Astro provides several ways for you to use images on your site, whether they are stored locally inside your project, linked to from an external URL, or managed in a CMS or CDN!

See the full API reference for the and components. Where to store images src/ vs public/ We recommend that local images are kept in src/ when possible so that Astro can transform, optimize and bundle them. Files in the /public directory are always served or copied into the build folder as-is, with no processing.

Your local images stored in src/ can be used by all files in your project: .astro, .md, .mdx, .mdoc, and other UI frameworks. Images can be stored in any folder, including alongside your content.

Store your images in the public/ folder if you want to avoid any processing or to have a direct public link to them.

Remote images You can also choose to store your images remotely, in a content management system (CMS) or digital asset management (DAM) platform. Astro can fetch your data remotely using APIs or display images from their full URL path.

For extra protection when dealing with external sources, Astro’s image components and helper function will only process (e.g. optimize, transform) images from authorized image sources specified in your configuration. Remote images from other sources will be displayed with no processing.

Images in .astro files In .astro files, a local image must be imported from its relative path. This import provides the src value for your image.

Remote and public/ images do not require importing, and instead require a URL (full, or relative path on your site) for src.

Import and use Astro’s native and components for optimized images. Astro syntax also supports writing an HTML tag directly, which skips image processing.

src/pages/blog/my-images.astro

import { Image } from ‘astro:assets’; import localBirdImage from ’../../images/subfolder/localBirdImage.png’;

See the full API reference for the and components.

Related recipe: Dynamically import images Display optimized images with the component Use the built-in Astro component to display optimized versions of:

your local images located within the src/ folder configured remote images from authorized sources can transform a local or authorized remote image’s dimensions, file type, and quality for control over your displayed image. The resulting tag includes alt, loading, and decoding attributes and infers image dimensions to avoid Cumulative Layout Shift (CLS).

What is Cumulative Layout Shift?

Cumulative Layout Shift (CLS) is a Core Web Vital metric for measuring how much content shifted on your page during loading. The component optimizes for CLS by automatically setting the correct width and height for your images.

src/components/MyComponent.astro

// import the Image component and the image import { Image } from ‘astro:assets’; import myImage from ’../assets/my_image.png’; // Image is 1600x900

The component accepts several component properties as well as any attributes accepted by the HTML tag.

The following example provides a class to the image component which will apply to the final element.

src/pages/index.astro

import { Image } from ‘astro:assets’; import myImage from ’../assets/my_image.png’;

Tip

You can also use the component for images in the public/ folder, or remote images not specifically configured in your project, even though these images will not be optimized or processed. The resulting image will be the same as using the HTML .

However, using the image component for all images provides a consistent authoring experience and prevents Cumulative Layout Shift (CLS) even for your unoptimized images.

Create responsive images with the component Added in: astro@3.3.0

Use the built-in Astro component to display a responsive image with multiple formats and/or sizes.

src/pages/index.astro

import { Picture } from ‘astro:assets’; import myImage from ’../assets/my_image.png’; // Image is 1600x900

<Picture src={myImage} formats={[‘avif’, ‘webp’]} alt=“A description of my image.” />

See details about the component properties in the astro:assets reference. Display unprocessed images with the HTML tag The Astro template syntax also supports writing an tag directly, with full control over its final output. These images will not be processed and optimized. It accepts all HTML tag properties, and the only required property is src.

Local images must be imported from the relative path from the existing .astro file, or you can configure and use an import alias. Then, you can access the image’s src and other properties to use in the tag.

Imported image assets match the following signature:

interface ImageMetadata { src: string; width: number; height: number; format: string; }

The following example uses the image’s own height and width properties to avoid Cumulative Layout Shift (CLS) and improve Core Web Vitals:

src/pages/posts/post-1.astro

// import local images import myDog from ’../../images/pets/local-dog.jpg’;

// access the image properties

Images in public/ For images located within public/ use the image’s file path relative to the public folder as the src value:

Remote images For remote images, use the image’s full URL as the src value:

Choosing vs The component optimizes your image and infers width and height (for images it can process) based on the original aspect ratio to avoid CLS. It is the preferred way to use images in .astro files whenever possible.

Use the HTML element when you cannot use the component, for example:

for unsupported image formats when you do not want your image optimized by Astro to access and change the src attribute dynamically client-side Setting Default Values Currently, there is no way to specify default values for all or components. Required attributes should be set on each individual component.

As an alternative, you can wrap these components in another Astro component for reuse. For example, you could create a component for your blog post images that receives attributes as props and applies consistent styles to each image:

src/components/BlogPostImage.astro

import { Image } from ‘astro:assets’;

const { src, …attrs } = Astro.props;

<Image src={src} {…attrs} />

Authorizing remote images You can configure lists of authorized image source URL domains and patterns for image optimization using image.domains and image.remotePatterns. This configuration is an extra layer of safety to protect your site when showing images from an external source.

Remote images from other sources will not be optimized, but using the component for these images will prevent Cumulative Layout Shift (CLS).

For example, the following configuration will only allow remote images from astro.build to be optimized:

astro.config.mjs export default defineConfig({ image: { domains: [“astro.build”], } });

The following configuration will only allow remote images from HTTPS hosts:

astro.config.mjs export default defineConfig({ image: { remotePatterns: [{ protocol: “https” }], } });

Using Images from a CMS or CDN Image CDNs work with all Astro image options. Use an image’s full URL as the src attribute in the component, an tag, or in Markdown notation. For image optimization with remote images, also configure your authorized domains or URL patterns.

Alternatively, the CDN may provide its own SDKs to more easily integrate in an Astro project. For example, Cloudinary supports an Astro SDK which allows you to easily drop in images with their CldImage component or a Node.js SDK that can generate URLs to use with an tag in a Node.js environment.

See the full API reference for the and components. Images in Markdown files Use standard Markdown syntax in your .md files. This syntax works with Astro’s Image Service API to optimize your local images stored in src/. Remote images and images stored in the public/ folder are not optimized.

src/pages/post-1.md

My Markdown Page

The tag is not supported for local images, and the and components are unavailable in .md files.

If you require more control over your image attributes, we recommend using Astro’s MDX integration to add support for.mdx file format. MDX allows adding components to Markdown and there are additional image options available in MDX.

Images in MDX files You can use Astro’s and components in your .mdx files by importing both the component and your image. Use them just as they are used in .astro files. The JSX tag is also supported for unprocessed images and uses the same image import as the HTML tag.

Additionally, there is support for standard Markdown syntax with no import required.

src/pages/post-1.mdx

title: My Page title

import { Image } from ‘astro:assets’; import rocket from ‘/blog-placeholder-3.jpg’;

My MDX Page

// Local image stored in the the same folder

// Local image stored in src/assets/

// Image stored in public/images/

// Remote image on another server

See the full API reference for the and components. Images in content collections Images in content collections will be processed the same way they are in Markdown and MDX depending on which file type you are using.

Additionally, you can declare an associated image for a content collections entry, such as a blog post’s cover image, in your frontmatter using its path relative to the current folder:

src/content/blog/my-post.md

title: “My first blog post” cover: ”./firstpostcover.jpeg” # will resolve to “src/content/blog/firstblogcover.jpeg” coverAlt: “A photograph of a sunset behind a mountain range.”

This is a blog post

The image helper for the content collections schema lets you validate and import the image.

src/content.config.ts import { defineCollection, z } from “astro:content”;

const blogCollection = defineCollection({ schema: ({ image }) => z.object({ title: z.string(), cover: image(), coverAlt: z.string(), }), });

export const collections = { blog: blogCollection, };

The image will be imported and transformed into metadata, allowing you to pass it as a src to , , or getImage().

The example below shows a blog index page that renders the cover photo and title of each blog post from the schema above:

src/pages/blog.astro

import { Image } from “astro:assets”; import { getCollection } from “astro:content”; const allBlogPosts = await getCollection(“blog”);

{ allBlogPosts.map((post) => (

)) }

Images in UI framework components The component, like any other Astro component, is unavailable inside UI framework components.

But, you can pass the static content generated by to a framework component inside a .astro file as children or using a named :

src/components/ImageWrapper.astro

import ReactComponent from ’./ReactComponent.jsx’; import { Image } from ‘astro:assets’; import stars from ’~/stars/docline.png’;

You can also use the framework’s own image syntax to render an image (e.g. in JSX, in Svelte).

Local images must first be imported to access their image properties such as src.

src/components/ReactImage.jsx import stars from “/blog-placeholder-3.jpg”;

export default function ReactImage() { return ( ) }

src/components/SvelteImage.svelte

Generating images with getImage() The getImage() function is intended for generating images destined to be used somewhere else than directly in HTML, for example in an API Route. When you need options that the and components do not currently support, you can use the getImage() function to create your own custom component.

See more in the getImage() reference.

Related recipe: Build a custom image component Alt Text Not all users can see images in the same way, so accessibility is an especially important concern when using images. Use the alt attribute to provide descriptive alt text for images.

This attribute is required for both the and components. If no alt text is provided, a helpful error message will be provided reminding you to include the alt attribute.

If the image is merely decorative (i.e. doesn’t contribute to the understanding of the page), set alt="" so that screen readers know to ignore the image.

Default image service Sharp is the default image service used for astro:assets. You can further configure the image service using the image.service option.

Note

When using a strict package manager like pnpm, you may need to manually install Sharp into your project even though it is an Astro dependency:

Terminal window pnpm add sharp