https://github.com/coreyward/sanity-image

React component for displaying well-optimized images from Sanity.io easily
https://github.com/coreyward/sanity-image

image images react sanity sanity-io srcset

Last synced: 18 days ago
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React component for displaying well-optimized images from Sanity.io easily

• Host: GitHub
• URL: https://github.com/coreyward/sanity-image
• Owner: coreyward
• Created: 2019-10-31T17:41:24.000Z (over 5 years ago)
• Default Branch: main
• Last Pushed: 2025-02-27T18:23:30.000Z (2 months ago)
• Last Synced: 2025-04-12T03:53:35.014Z (18 days ago)
• Topics: image, images, react, sanity, sanity-io, srcset
• Language: TypeScript
• Homepage:
• Size: 947 KB
• Stars: 123
• Watchers: 2
• Forks: 14
• Open Issues: 1
• Metadata Files:
  • Readme: README.md

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README

        
# sanity-image

[![Latest version](https://img.shields.io/npm/v/sanity-image?label=version&color=brightGreen&logo=npm)](https://www.npmjs.com/package/sanity-image)

[![Open issues](https://img.shields.io/github/issues/coreyward/sanity-image)](https://github.com/coreyward/sanity-image/issues)

![React version compatibility](https://img.shields.io/badge/dynamic/json?color=blue&label=react%20versions&query=peerDependencies.react&url=https%3A%2F%2Fraw.githubusercontent.com%2Fcoreyward%2Fsanity-image%2Fmain%2Fpackage.json)

A well-considered React component for displaying images from Sanity. At a

glance:

- Outputs a single `` tag, no nested DOM structure to mess with

- Zero styling included so you can style it however you want…it's just an `img`

  tag!

- Supports low-quality image previews out of the box, without build-time

  penalties (native lazy loading)

- Generates a `srcSet` automatically based on the `width` you specify

- Dynamic `srcSet` factor based on image output width

- Knows _exactly_ what size the image will be and sets `width` and `height`

  attributes accordingly

- Supports `crop` and `hotspot` values from the Sanity Studio

- Automatically crops to the most “interesting” part of the image if the aspect

  ratio changes and no `hotspot` is provided

- Images are _never_ scaled up

- Tiny 4kb bundle size (2kb gzipped)

- No dependencies

- TypeScript support

- Works with Gatsby, Next.js, and any other React-based framework

- Polymorphic component (supports `as` prop to render as a custom component)

## Quick Start

### Install it:

```sh

yarn add sanity-image

# or

npm install sanity-image

```

### Use it:

You can find the full writeup on getting going below, but in the interest of

making it easy to see if this is the thing you are looking for, here’s a quick

example of most of what you’ll need to know:

**Simplest Case**:

This will render the image out assuming it will be displayed at half its

original width with a srcSet included (multiplies vary based on original image

size):

```tsx

import { SanityImage } from "sanity-image"

const YourSweetComponent = ({ image }: ComponentProps) => (

  

)

```

**More full-featured example**:

```tsx

import { SanityImage } from "sanity-image"

const YourSweetComponent = ({ image }: ComponentProps) => (

  

)

export default YourSweetComponent

```

That’s the gist. Read on for more. 👇

## Details

How it works at a glance:

- The image ID is parsed to determine the source image dimensions and format

- SVG images get special treatment from the Sanity Image API (they don't support

  params), so they're handled a bit differently (check `SanityImage.ts` for

  details)

- All other images have `src` and `srcSet` props generated based on the `width`

  and `height` props you pass in (or the image dimensions if you don't pass in a

  width or height)

- The `srcSet` widths depend on the size of the output image and the original

  image; there's some logic to avoid wasteful tiny images or giant jumps in size

  between large entries (see `dynamicMultipliers` in `urlBuilder.ts`)

- Values in the `srcSet` are never duplicated and never upscale the image

- Since we can compute the output dimensions of the image in all cases, the

  `width` and `height` attributes are set automatically to avoid layout shifts

- A few image params are applied by default:

  - `auto=format` - Sanity will use AVIF images if they're supported by the

    browser (https://www.sanity.io/help/avif) (note: if you specify `fm`

    manually, this won't be set)

  - `fit` - if the image aspect ratio isn't changed, this will be set to `max`;

    if the aspect ratio will change it's set to `crop`; you don't really need to

    worry about this though

  - `q` - the quality is set to 75 by default, but you can override it with the

    `queryParams` prop

- The `loading` attribute will be set to `lazy` if it isn't supplied; use

  `loading="eager"` for images above the fold

- The `alt` attribute will be set to an empty string if it isn't supplied; set

  it if it isn't a decorative image!

- By default it renders an `img` tag (two if you pass in a `preview`), but you

  can pass in a custom component to render as using the `as` prop (see the

  `SanityImage.test.tsx` file for an example of this)

- If you wanna get weird you can also import the `buildSrc` and `buildSrcSet`

  exports to do your own thing with. You get a lot of the magic still this way

  with a skosh more control.

- Similarly, the `parseImageId` function is available as a named export; it

  takes an image ID and returns an object with the image id, dimensions, and

  format.

- Query params passed to Sanity are all sorted and minimized like heck for

  improved caching and smaller URLs. Pass in a `height` only? Don't be alarmed,

  but it'll be converted to a `w` param without altering what you're asking

  Sanity for. Ask for `mode="cover"` but the aspect ratio matches the source?

  It'll be ignored and fall back to `fit=max` with just a `w` param. You get the

  idea (I hope, or at least, I'm pretending, but no judgement if you don't, it's

  definitely 11:09pm and I'm on fumes)

## Props

This is mostly copied and reformatted from the `types.ts` file; if you're

comfortable with TypeScript, that might give you more detail.

- `id` (string) — Required - The Sanity Image ID (`_id` or `_ref` field value)

- `mode` ("cover" | "contain") — Optional - Use `cover` to crop the image to

  match the requested aspect ratio (based on `width` and `height`). Use

  `contain` to fit the image to the boundaries provided without altering the

  aspect ratio. Defaults to `"contain"`. See the image below for a comparison.

- `width` (number) — Optional - The target width of the image in pixels. Only

  used for determining the dimensions of the generated assets, not for layout.

  Use CSS to specify how the browser should render the image instead.

- `height` (number) — Optional - The target height of the image in pixels. Only

  used for determining the dimensions of the generated assets, not for layout.

  Use CSS to specify how the browser should render the image instead.

- `hotspot` (`{ x: number, y: number }`) — Optional - The hotspot coordinates to

  use for the image. Note: hotspot `width` and `height` are not used.

- `crop` (`{ top: number, bottom: number, left: number, right: number }`) —

  Optional - The crop coordinates to use for the image.

- `preview` (string) — Optional - A low-quality image preview to use while the

  full-size image is loading. This should be a base64-encoded image string.

- `as` (React.ElementType) — Optional - The component to render as. Defaults to

  `"img"`.

- `baseUrl` (string) — Optional - The base URL to use for the image. If not

  specified, the `projectId` and `dataset` props will be used to construct the

  URL.

- `projectId` (string) — Optional - The Sanity project ID to use for the image.

  Only used if `baseUrl` is not specified.

- `dataset` (string) — Optional - The Sanity dataset to use for the image. Only

  used if `baseUrl` is not specified.

- `queryParams` (object) — Optional - An object of query parameters to pass to

  the Sanity Image API. See the

  [Sanity Image API documentation](https://www.sanity.io/docs/image-urls) for a

  list of available options.

That's the gist. There's a ton more in the inline comments and types and such,

and I'll add more details as I think of them. Feel free to open an issue or

start a discussion if you have questions or suggestions, or find me on the

Sanity Slack!

  ⚠️ “Help! My full-size image isn’t loading!"

`SanityImage` is relying on browser-native deferred image loading. This relies

on the `` element being visible on the page to trigger loading

automatically. If the image is hidden or covered by another element, it may

never be loaded.

For example, if you are using `overflow: hidden` on a parent element, the image

might be positioned in a way that it is not treated as visible by the browser.

This can also happen if you have `display: none` on the image or a parent

element, or if the image is positioned off-screen (e.g., in a carousel, or

waiting for an animation to reveal it).

Inspecting the DOM in your browser’s dev tools and checking the position of the

`` element with the `data-loading` attribute can help you identify the

issue usually. Once you can identify the cause of the image being hidden, you

can adjust the CSS styles on the `img[data-loading]` element to make it visible.

For reference, the full-size image sits immediately adjacent to the preview

image and has the following default styles _while loading_:

```css

position: absolute;

width: 10px !important; /* must be > 4px to be lazy loaded */

height: 10px !important; /* must be > 4px to be lazy loaded */

opacity: 0;

zindex: -10;

pointerevents: none;

userselect: none;

```

## Tips

### Choosing the right `mode`

If you are providing only one dimension (`width` or `height`, but not both), it

doesn't matter since the behavior will be the same.

- **Contain** mode will treat the dimensions you provide as boundaries, resizing

  the image to fit inside of them. The output image will match the aspect ratio

  of the original image (i.e., no cropping will occur).

- **Cover** mode will treat the dimensions you provide as a container, resizing

  the image to completely fill the dimensions. The output image will match the

  aspect ratio of the dimensions you provide.

Here's a visual of this in action:

![Sanity Image Mode Explanation](https://github.com/user-attachments/assets/82125edb-2081-448e-9f06-c90d4f0bbf34)

### Wrap it internally

To improve the DX of using `sanity-image`, create a wrapper component in your

app that sets the `baseUrl` prop (or `projectId` and `dataset`). This keeps the

configuration in one place and gives you an entry point to add any other logic

you might need. There's a

[full `ImageWrapper` example](https://github.com/coreyward/sanity-image/blob/main/examples/ImageWrapper.tsx)

in the examples folder including comments. Here's a simplified version of that

example for quick reference:

```tsx

import * as React from "react"

import { SanityImage, type WrapperPRops } from "sanity-image"

export const Image = (

  props: WrapperProps

) => 

```

  👩‍🎤 Using Emotion’s `jsxImportSource`? Read this.

When you set the `jsxImportSource` to `@emotion/react` it replaces some core

React types with those of its own. This allows Emotion’s polymorphic components

to work, but it also makes typing a polymorphic component like `` a

bit harder. This is okay when it's used directly, but the wrapper approach winds

up breaking it—the use of `Omit` to remove configuration props breaks the

polymorphism and prompts TS to complain about unexpected props.

I am not a TS wizard, alas, and despite lots of reading and attempting to make

something that works out of the box for Emotion, I have not managed to do so.

Instead I recommend using `@ts-expect-error` on the `` line in your

wrapper. This will tell TS to ignore the props we're passing in, but it will

still ensure your in-app `` component works as expected with full

polymorphic type support.

```tsx

export const Image = (

  props: WrapperProps

) => (

  /* @ts-expect-error Emotion types are incompatible with polymorphic component */

  

)

```

### Styling your images

I recommend setting something like the following CSS for images in your project,

then overriding styles as needed. This will ensure images act like block-level

elements with infinitely scalable contents even with the `width` and `height`

attributes set. It also makes it easier to handle responsiveness—if your

container gets smaller, the image gets smaller.

```css

img {

  display: block;

  max-width: 100%;

  width: 100%;

  height: auto;

}

```

Here's an example of how that works when using, for example, a 3-column grid

that fills the viewport until it is a maximum of 1,200px wide (plus padding).

This produces columns that are 390px at most on desktop:

```jsx



  {["image-a", "image-b", "image-c"].map((imageId) => (

    


      

    

  ))}



```


If you need these images to all match in height, it's a good idea to switch to

`cover` mode. With the height set to 260px and `mode="cover"`, this will produce

images with a 3:2 aspect ratio that fill the column width even if the source

image is too small:

```jsx

```

In this example we don't pass a `hotspot` value, so the image will be cropped

based on what Sanity thinks is the most interesting part of the image since

`SanityImage` automatically sets `crop=entropy` in these cases. If you want to

override that, you can pass a `hotspot` value.

### Background images

Using `SanityImage` for background images is easy, you just style the image to

match the expectations of your mockup. In most cases that means setting

`position: relative` on the container you want to fill, then using absolute

positioning for the image. Here’s an example:

```jsx

  

  


    
Your big hero copy

    Get started

  


```

This will cause the `section` to be sized based on the content inside of the

`div`, and the image will be sized to fill the entire section. The aspect ratio

of the image will be maintained due to the use of `object-fit: cover`. Note that

we are still using `mode="contain"` for `SanityImage` here. If you have a rough

idea of the height your section, you can set `height` and `mode="cover"` which

will prevent, for example, a portrait orientation image from being retrieved and

cropped by the browser.

Since the z-index is set higher on the `div` containing the content, it will

show above the image. This example also sets `user-select: none` on the image to

prevent the image from being selected when the user clicks and drags on the page

to make it behave more like a traditional background image.

### Fetching data from Sanity via GROQ

If you're using Sanity's GROQ query language to fetch data, here is how I

recommend fetching the fields you need from a typical image with the hotspot,

crop, and low-quality image preview included:

```groq

"id": asset._ref,

"preview": asset->metadata.lqip,

hotspot { x, y },

crop {

  bottom,

  left,

  right,

  top,

}

```

## License

Copyright ©2023-2025 Corey Ward. Available under the

[MIT License](https://github.com/coreyward/sanity-image/blob/main/LICENSE).