Gatsby Image plugin
Examples
This guide will show you how to configure your images, including choosing layouts, placeholders and image processing options. While most of these options are available regardless of where you source your images, be sure to refer to the documentation of your source plugin if you are using images from a CMS, as the exact options are likely to vary.
Components
The Gatsby Image plugin includes two components to display responsive images on your site. One is used for static and the other for dynamic images.
StaticImage
: Use this if the image is the same every time the component is used. Examples: site logo, index page hero imageGatsbyImage
: Use this if the image is passed into the component as a prop, or otherwise changes. Examples: Blog post hero image, author avatar
If you would like to learn how to set up the image plugins and use these components on your site, see the how-to guide.
These are props that can be passed to the components:
Shared props
The following props can be passed to both GatsbyImage
and StaticImage
. You may also use any valid <img>
tag props, which are forwarded to the underlying <img>
element.
Prop | Type | Default | Description |
---|---|---|---|
alt (Required) | string | Alternative text, passed to the <img> tag. Required for accessibility. | |
as | ElementType | "div" | The HTML element used for the outer wrapper. |
loading | "eager" ∣ "lazy" | "lazy" | Loading behavior for the image. You should set this to "eager" for above-the-fold images to ensure they start loading before React hydration. |
className | string | CSS class applied to the outer wrapper. | |
imgClassName | string | CSS class applied to the <img> element. | |
style | CSSProperties | Inline styles applied to the outer wrapper. | |
imgStyle | CSSProperties | Inline styles applied to the <img> element. | |
backgroundColor | string | transparent | Background color applied to the wrapper. |
objectFit | See MDN doc | cover | Resizing behavior for the image within its container. |
objectPosition | See MDN doc | 50% 50% | Position of the image within its container. |
StaticImage
The StaticImage
component can take all image options as props, as well as all shared props. Additionally, it takes this prop:
Prop | Type | Description |
---|---|---|
src (Required) | string | Source image, processed at build time. Can be a path relative to the source file, or an absolute URL. |
Restrictions on using StaticImage
The images are loaded and processed at build time, so there are restrictions on how you pass props to the component. The values need to be statically-analyzed at build time, which means you can’t pass them as props from outside the component, or use the results of function calls, for example. You can either use static values, or variables within the component’s local scope. See the following examples:
This does not work:
…and nor does this:
You can use variables and expressions if they’re in the scope of the file, e.g.:
If you find yourself wishing you could use a prop for the image src
then it’s likely that you should be using a dynamic image.
Using StaticImage
with CSS-in-JS libraries
The StaticImage
component does not support higher-order components, which includes the styled
function from libraries such as Emotion and styled-components. The parser relies on being able to identify StaticImage
components in the source, and passing them to a function means this is not possible.
If you use Emotion you can use the provided css
prop instead:
Unfortunately the css
prop from styled-components turns the code into a styled
function under the hood and as explained above StaticImage
doesn’t support that syntax.
You can also use a regular style
or className
prop. Note that in all of these cases the styling is applied to the wrapper, not the image itself. If you need to style the <img>
tag, you can use imgStyle
or imgClassName
. The className
or imgClassName
prop is helpful if your styling library is giving you a computed class name string instead of the computed styles (e.g. if you use libraries like linaria).
GatsbyImage
This component accepts all shared props, as well as the one below. These props are passed directly to the component, and are not to be confused with image options, which are passed to the GraphQL resolver when using dynamic images.
Prop | Type | Description |
---|---|---|
image (Required) | GatsbyImageData | The image data object, returned from the gatsbyImageData resolver. |
Image options
There are a few differences between how you specify options for StaticImage
and GatsbyImage
:
How to pass options: When using
StaticImage
, options are passed as props to the component, whereas for theGatsbyImage
component they are passed to thegatsbyImageData
GraphQL resolver.Option values: In the
StaticImage
component, props such aslayout
andplaceholder
take a string, while the resolver takes a a GraphQL enum, which is upper case by convention and is not quoted like a string. Both syntaxes are shown in the reference below.
Important: For dynamic images, these options are for the gatsbyImageData
resolver on sharp nodes. If you are using gatsbyImageData
from a different plugin, such as a CMS or image host, you should refer to that plugin’s documentation for the options, as they will differ from these. Static images use sharp under the hood, so these options apply when using the StaticImage
component too.
It is a very good idea to use the GraphiQL IDE when writing your gatsbyImageData
queries. It includes auto-complete and inline documentation for all of the options and lets you see the generated image data right inside the browser.
Both static and dynamic images have the following options available:
Option | Default string/enum value | Description |
---|---|---|
layout | "constrained" / CONSTRAINED | Determines the size of the image and its resizing behavior. |
aspectRatio | Source image aspect ratio | Force a specific ratio between the image’s width and height. |
width /height | Source image size | Change the size of the image. |
placeholder | "dominantColor" /DOMINANT_COLOR | Choose the style of temporary image shown while the full image loads. |
formats | ["auto","webp"] /[AUTO,WEBP] | File formats of the images generated. |
transformOptions | {fit: "cover", cropFocus: "attention"} /{fit: COVER, cropFocus: ATTENTION} | Options to pass to sharp to control cropping and other image manipulations. |
See all options.
layout
The image components support three types of layout, which determine the image sizes that are generated, as well as the resizing behavior of the image itself in the browser.
Layout | Component prop value | Resolver prop value | Description |
---|---|---|---|
Constrained | "constrained" | CONSTRAINED | This is the default layout. It displays the image at the size of the source image, or you can set a maximum size by passing in width or height ). If the screen or container size is less than the width of the image, it scales down to fit, maintaining its aspect ratio. It generates smaller versions of the image so that a mobile browser doesn’t need to load the full-size image. |
Fixed | "fixed" | FIXED | This is a fixed-size image. It will always display at the same size, and will not shrink to fit its container. This is either the size of the source image, or the size set by the width and height props. Only use this if you are certain that the container will never need to be narrower than the image. |
Full width | "fullWidth" | FULL_WIDTH | Use this for images that are always displayed at the full width of the screen, such as banners or hero images. Like the constrained layout, this resizes to fit the container. However it is not restricted to a maximum size, so will grow to fill the container however large it is, maintaining its aspect ratio. It generates several smaller image sizes for different screen breakpoints, so that the browser only needs to load one large enough to fit the screen. You can pass a breakpoints prop if you want to specify the sizes to use, though in most cases you can allow it to use the default. |
You can compare the layouts in the video below:
To set the layout, pass in the type to the layout prop. e.g.
For a dynamic image, pass it to the resolver:
width
/height
Layouts: fixed and constrained
Size props are optional in GatsbyImage
and StaticImage
. Because the images are processed at build time, the plugin knows the size of the source image and can add the correct width and height to the <img>
tag, so it displays correctly with no layout jumping. However, if you want to change the display size you can use the size options to do this.
For a fixed
layout, these define the size of the image displayed on screen. For a constrained
image these define the maximum size, as the image will scale down to fit smaller containers if needed.
If you set just one of these, the source image is resized to that width or height while maintaining aspect ratio. If you include both then it is also cropped if needed to ensure it is that exact size.
aspectRatio
Layouts: fixed, constrained, and fullWidth
The aspectRatio
prop forces an image to the specified aspect ratio, cropping if needed. The value is a number, but can be clearer to express as a fraction, e.g. aspectRatio={16/9}
For fixed
and constrained
images, you can also optionally pass either a width
or height
, and it will use that to calculate the other dimension. For example, if you pass width={800} aspectRatio={4/3}
then height
will be set to the width divided by the aspect ratio: so 600
. Passing 1
as the aspectRatio will crop the image to a square. If you don’t pass a width or height then it will use the source image’s width.
For fullWidth
images you don’t specify width or height, as it resizes to fit the screen width. Passing aspectRatio
will crop the image if needed, and the height will scale according to the width of the screen. For example, if you set the aspectRatio to 16/9
then when the image is displayed full width on a screen that is 1280px wide, the image will be 720 pixels high.
Note: There are several advanced options that you can pass to control the cropping and resizing behavior. For more details, see the transformOptions
reference.
placeholder
Gatsby image components are lazy-loaded by default, which means that if they are offscreen they are not loaded by the browser until they come into view. To ensure that the layout does not jump around, a placeholder is displayed before the image loads. You can choose one of three types of placeholder (or not use a placeholder at all):
Placeholder | Component prop value | Resolver prop value | Description |
---|---|---|---|
Dominant color | "dominantColor" | DOMINANT_COLOR | The default placeholder. This calculates the dominant color of the source image and uses it as a solid background color. |
Blurred | "blurred" | BLURRED | This generates a very low-resolution version of the source image and displays it as a blurred background. |
Traced SVG | "tracedSVG" | TRACED_SVG | This generates a simplified, flat SVG version of the source image, which it displays as a placeholder. This works well for images with simple shapes or that include transparency. |
None | "none" | NONE | No placeholder. You can use the background color option to set a static background if you wish. |
formats
Default component prop value: ["auto", "webp"]
. Default resolver prop value: [AUTO, WEBP]
The Gatsby Image plugin supports four output formats: JPEG, PNG, WebP and AVIF. By default, the plugin generates images in the same format as the source image, as well as WebP. For example, if your source image is a PNG, it will generate PNG and WebP images. In most cases, you should not change this. However, in some cases you may need to manually set the formats. One reason for doing so is if you want to enable support for AVIF images. AVIF is a new image format that results in significantly smaller file sizes than alternative formats. It currently has limited browser support, but this is likely to increase. It is safe to include as long as you also generate fallbacks for other browsers, which the image plugin does automatically by default.
transformOptions
These values are passed in as an object to transformOptions
, either as a prop to StaticImage
, or to the resolver for dynamic images. They are advanced settings that most people will not need to change. Any provided object is merged with the defaults below.
Option name | Default | Description |
---|---|---|
grayscale | false | Convert image to grayscale |
duotone | false | Add duotone effect. Pass false , or options object containing {highlight: string, shadow: string, opacity: number} |
rotate | auto | Rotate the image. Value in degrees. |
trim | 10 | Trim “boring” pixels. Value is the threshold. See the sharp documentation. |
cropFocus | "attention" /ATTENTION | Controls crop behavior. See the sharp documentation for strategy, position and gravity. |
fit | "cover" /COVER | Controls behavior when resizing an image and proving both width and height. See the sharp documentation. |
All options
The Gatsby Image plugin uses sharp for image processing, and supports passing through many advanced options, such as those affecting cropping behavior or image effects including grayscale or duotone, as well as options specific to each format.
Option | Default | Description |
---|---|---|
layout | "constrained" / CONSTRAINED | Determines the size of the image and its resizing behavior. |
width /height | Source image size | Change the size of the image. |
aspectRatio | Source image aspect ratio | Force a specific ratio between the image’s width and height. |
placeholder | "dominantColor" /DOMINANT_COLOR | Choose the style of temporary image shown while the full image loads. |
formats | ["auto","webp"] /[AUTO,WEBP] | File formats of the images generated. |
transformOptions | {fit: "cover", cropFocus: "attention"} | Options to pass to sharp to control cropping and other image manipulations. |
sizes | Generated automatically | The <img> sizes attribute, passed to the img tag. This describes the display size of the image, and does not affect generated images. You are only likely to need to change this if your are using full width images that do not span the full width of the screen. |
quality | 50 | The default image quality generated. This is overridden by any format-specific options |
outputPixelDensities | For fixed images: [1, 2] For constrained: [0.25, 0.5, 1, 2] | A list of image pixel densities to generate. It will never generate images larger than the source, and will always include a 1x image. The value is multiplied by the image width, to give the generated sizes. For example, a 400 px wide constrained image would generate 100 , 200 , 400 and 800 px wide images by default. Ignored for full width layout images, which use breakpoints instead. |
breakpoints | [750, 1080, 1366, 1920] | Output widths to generate for full width images. Default is to generate widths for common device resolutions. It will never generate an image larger than the source image. The browser will automatically choose the most appropriate. |
blurredOptions | None | Options for the low-resolution placeholder image. Ignored unless placeholder is blurred. |
tracedSVGOptions | None | Options for traced placeholder SVGs. See potrace options. Ignored unless placeholder is traced SVG. |
jpgOptions | None | Options to pass to sharp when generating JPG images. |
pngOptions | None | Options to pass to sharp when generating PNG images. |
webpOptions | None | Options to pass to sharp when generating WebP images. |
avifOptions | None | Options to pass to sharp when generating AVIF images. |
Customizing the default options
You might find yourself using the same options (like placeholder
, formats
etc.) with most of your GatsbyImage
and StaticImage
instances.
You can customize the default options with gatsby-plugin-sharp
.
The following configuration describes the options that can be customized along with their default values:
Helper functions
There are a number of utility functions to help you work with gatsbyImageData
objects. We strongly recommend that you do not try to access the internals of these objects directly, as the format could change.
getImage
Safely get a gatsbyImageData
object. It accepts several different sorts of objects, and is null-safe, returning undefined
if the object passed, or any intermediate children are undefined.
If passed a File
object, it will return file?.childImageSharp?.gatsbyImageData
. If passed a node such as a ContentfulAsset
that includes a gatsbyImageData
field, it will return the gatsbyImageData
object. If passed a gatsbyImageData
object itself, it will return the same object.
getSrc
Get the default image src
as a string. This will be the fallback, so usually jpg or png. Accepts the same types as getImage
.
getSrcSet
Get the default image srcset
. This will be the fallback, so usually jpg or png.
withArtDirection
By default, the plugin displays different image resolutions at different screen sizes, but it also supports art direction, which is where a visually-different image is displayed at different sizes. This could include displaying a simplified logo or a tighter crop on a profile picture when viewing on a small screen. To do this, you can use the withArtDirection
function. You need both images available from GraphQL, and you should be able to write a media query for each size.
The first argument is the default image. This is displayed when no media queries match, but it is also used to set the layout, size, placeholder and most other options. You then pass an array of “art directed images” which are objects with media
and image
values.
When the screen is less than 1024px wide, it will display smallImage
. Otherwise, it will display largeImage
.
The aspect ratio is set by the default image, and doesn’t automatically change with the different sources. The way to handle this is to use CSS media queries. For example, you could use this CSS to change the size of the container in small images:
You can then apply this using plain CSS, or the styling system of your choice. e.g.