gatsby-plugin-sanity-image
v0.13.5
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Gatsby plugin providing easy responsive behavior for Sanity-hosted images
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gatsby-plugin-sanity-image
The well-considered marriage between Sanity’s image assets and Gatsby you’ve been looking for.
- Outputs a single
<img>
tag, no nested DOM structure to mess with - Supports low-quality image previews out of the box, without build-time penalties (native lazy loading)
- Generates a
srcSet
automatically based on thewidth
you specify in your component code (meaning you can change it on the fly!) - Applies Sanity hotspot data as the
object-position
in case you need it - Computes cropped dimensions and drops
srcSet
entries that are larger than the source dimensions when appropriate (follows Sanity’s image-url parameters) - Configure image quality, resizing behavior, file format, and more with Sanity’s Image API
At a Glance
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 what using it looks like:
import Image from "gatsby-plugin-sanity-image"
const YourSweetComponent = ({ image }) => (
<Image
// pass asset, hotspot, and crop fields
{...image}
// tell Sanity how large to make the image (does not set any CSS)
width={500}
// style it how you want it
style={{
width: "100%",
height: "100%",
objectFit: "cover",
}}
/>
)
export default YourSweetComponent
export const query = graphql`
{
sanityDocumentOfSomeKind {
sweetImage {
...ImageWithPreview
}
}
}
`
That’s the gist, folks. Read on for the full scoop!
Getting Started
Install it
yarn add gatsby-plugin-sanity-image
Configure it
ℹ️ Note: If this is your first time adding a Gatsby plugin, be sure to read this guide first—the below is a shorthand notation.
Simple configuration:
{
resolve: "gatsby-plugin-sanity-image",
options: {
// Sanity project info (required)
projectId: "abcd1234",
dataset: "production",
},
}
If you have custom image types in Sanity (e.g. mainImage
that is of type
image
) you’ll need to add one more option before you move on. Check the full
example or the Configuration Directives below.
// Full configuration:
{
resolve: "gatsby-plugin-sanity-image",
options: {
// Sanity project info (required)
projectId: "abcd1234",
dataset: "production",
// Custom image types are also supported. For example, if you have a
// `mainImage` type in Sanity, it winds up in Gatsby as `SanityMainImage`,
// and so you would add "SanityMainImage" to the customImageTypes array.
customImageTypes: [],
// This config directive allows you to specify the field that should be
// retrieved and used as alt text when no `alt` prop is passed to the image
// component. See docs for more detail.
altFieldName: "alt",
// SanityImage will warn you if you do not set an alt prop/attribute. If
// you don't want this behavior, you can disable this here. By default this
// is only enabled in development.
warnOnMissingAlt: process.env.NODE_ENV === "development",
// When no `alt` prop is available, SanityImage can default to setting an
// empty string value. This can prevent accessibility audits from detecting
// images that should have an alt value, but enabling it allows you to only
// set alt text when it is needed.
emptyAltFallback: false,
// Additional params to pass to @sanity/image-url for every image. The
// default is shown here, so you can omit the directive if you are happy
// with what you see here.
defaultImageConfig: {
quality: 75,
fit: "max",
auto: "format",
},
// ########################################################################
// Configuration directives below this point are rarely needed. If you #
// aren't confident you need them, you probably do not need them. #
// ########################################################################
// If you prefer a different fragment name, such as `MagicImage`, enter it
// here. This needs to be unique amongst your GraphQL types. `WithPreview`
// will be appended for the second fragment (e.g. MagicImageWithPreview).
fragmentName: "Image",
// By default, image fields are typed as SanityImage, but there are cases
// where you might want to use a custom schema or where custom image types
// are not under the SanityImage type. In this case, you
// can alter the type that the fragment is defined
// on here without redefining the fragments.
fragmentTypeName: "SanityImage",
// If you prefer to retreive data another way or if you want to define the
// fragment you use separately, you can opt-out of having fragments included
// entirely.
includeFragments: true,
},
}
Don’t forget to restart gatsby develop
after you update your
gatsby-config.js
!
Usage
- Query for the image fields
- Pass the retrieved fields as props to the
SanityImage
component - Use it like normal—it's just an
img
tag! 🤯😇
Querying for image data via GraphQL
This plugin includes two GraphQL fragments that will fetch the fields needed for display from any Sanity image asset. You do not have to use them, but they are convenient and help keep you away from confusing bugs.
In most cases, you'll want to use the ImageWithPreview
fragment:
export const query = graphql`
{
sanitySomeDocument {
yourImageField {
...ImageWithPreview
}
}
}
`
This will retrieve the asset
, hotspot
, and crop
fields and includes a
low-quality image preview that will be shown while the full image is loading.
Opting out of blurry preview images
If you have an image that you do NOT want to use the preview image for, you can
opt to use the simpler Image
fragment instead. This has all of the same fields
with the exception of the preview. This will keep your HTML files a bit lighter,
but you may wind up with more cumulative layout shift as the browser fetches the
image dimensions and evaluates your styles.
Note: If you are using an SVG image, you probably do not want to fetch the
preview since it’ll get thrown away—the SanityImage
component aborts early on
SVG images to avoid generating meaningless srcSet
data that reduces cache
efficiency.
Using the SanityImage
component
The data you fetched from GraphQL should be an object that you can expand
straight into the SanityImage
component and just work. If you used the
ImageWithPreview
fragment, SanityImage
will do the right thing
automatically.
import SanityImage from "gatsby-plugin-sanity-image"
const YourComponent = ({ yourImageFieldData }) =>
<SanityImage {...yourImageFieldData} width={300} alt="Sweet Christmas!">
<!--
Using {baseUrl} below to refer to a string with this format:
https://cdn.sanity.io/images/{projectId}/{dataset}/{imageId}?w=300&h=600&q=75&fit=max&auto=format
-->
<img
src="{baseUrl}"
srcset="
{baseUrl}&dpr=0.5 150w,
{baseUrl}&dpr=0.75 225w,
{baseUrl}&dpr=1 300w,
{baseUrl}&dpr=1.5 450w,
{baseUrl}&dpr=2 600w
"
loading="lazy"
alt="Sweet Christmas!"
class="css-1jku2jm-SanityImage"
/>
Note that SanityImage
is not doing anything to style your image based on the
width or height you provide (aside from setting a class with object-position
set, should you choose to use it). In practice, it's rare that these values
align consistently with a particular layout, and library control of this makes
it difficult to predict the output given a particular input.
Instead you can style the resulting img
tag just like any other element.
SanityImage
will pass through className
and style
props, and it makes no
assumptions about your image presentation.
SanityImage
is relying on browser-native deferred image loading. This
generally works fine in browsers that support it, but there are situations where
the unloaded image is hidden or covered, resulting in the full image never
loading.
If this happens, you can override the styles set on the full-size image using
the img[data-loading]
selector. This image sits immediately adjacent to the
spaceball image and has the following default styles while loading:
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;
Component Props
For convenience, __typename
, _type
, and _key
props will be ignored. Other
props will be passed through to the final img
element (e.g. native HTML
attributes).
*️⃣ = Required
| Prop | Type | Description |
| ----------- | ------ | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| asset
*️⃣ | Object | The asset
object fetched from GraphQL. Should have an _id
property on it, and possibly metadata
(if you're using low-quality image previews). |
| crop
| Object | The crop
values fetched from GraphQL (top
, right
, bottom
, and left
) |
| hotspot
| Object | The hotspot
values fetched from GraphQL (width
, height
, x
, and y
) |
| width
*️⃣ | Number | This will be used as a target value to generate a srcSet
of images both smaller and larger. |
| height
| Number | Used to further constrain the image. Note: due to a bug in the @sanity/image-url
library, setting this will cause fit
modes to be largely ignored. |
| config
| Object | Parameters for @sanity/image-url
. Full list here. |
| options
| Object | See below. |
Options
If enabled, SanityImage
will attempt to compute the final aspect ratio and use
it to set width
and height
attributes on both the low-quality preview image
as well as the final image. This does not currently take into account any
config
options, including fit
modes or transforming options like rect
or
orientation
.
Configuration Directives
*️⃣ = Required
| Option | Type | Default | Description |
| ----------------------------- | ------- | --------------- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| projectId
*️⃣ | String | | Sanity Project ID |
| dataset
*️⃣ | String | | Sanity Dataset ID |
| customImageTypes
| Array | []
| If you would like to use the Image
and ImageWithPreview
fragments on custom image types, specify all custom type names in the customImageTypes
array. For more detail, follow this guide. |
| altFieldName
| String | null
| If you are adding alt text directly to image assets in your Sanity Studio (e.g. via a plugin like sanity-plugin-media), this plugin can include that field in the Image
and ImageWithPreview
fragments and utilize it as the default/fallback alt
attribute value when no alt
prop is passed to the SanityImage
component. |
| warnOnMissingAlt
| Boolean | See note 👉 | SanityImage will warn you if you do not set an alt prop/attribute. If you don't want this behavior, you can disable this here. By default this is only enabled in development. |
| emptyAltFallback
| Boolean | false
| When no alt
prop is available, SanityImage can default to setting an empty string value. This can prevent accessibility audits from detecting images that should have an alt value, but enabling it allows you to only set alt text when it is needed. |
| defaultImageConfig
| Object | See below. | Additional params to pass to the Sanity image URL builder. These will be converted into function calls against @sanity/image-url
. Here is the full list of methods available. |
| Less common directives ⬇️ | | | It is unlikely you will need to use these. Proceed with caution. |
| fragmentName
| String | "Image"
| If you prefer a different fragment name, such as MagicImage
, enter it here. This needs to be unique amongst your GraphQL types. WithPreview
will be appended for the second fragment (e.g. MagicImageWithPreview). |
| fragmentTypeName
| String | "SanityImage"
| By default, image fields are typed as SanityImage, but there are cases where you might want to use a custom schema or where custom image types are not under the SanityImage
type. In this case, you can alter the type that the fragment is defined on without redefining the fragments. |
| includeFragments
| Boolean | true
| If you prefer to retreive data another way or if you want to define the fragment you use separately, you can opt-out of having fragments included entirely. |
The default value for defaultImageConfig
is as follows:
{
quality: 75, // use reasonable lossy compression level
fit: "max", // like `object-fit: contain`, but never scaling up
auto: "format" // automatically select next-gen image formats on supporting browsers
}
More things to know
- If you don't specify
width
the uploaded image width is used. - You are encouraged to use the
sizes
attribute to steer browsers to select the most appropriate image from thesrcSet
based on the viewport width - You can target the low-quality image preview element via
img[data-lqip]
should you want to style it differently
License
Copyright ©2022 Corey Ward. Available under the MIT License.