. This article explains the history of responsive images in responsive design, why they're necessary, and how all these technologies work together to save bandwidth and provide a better experience for users. The primary goal of react-imgix is to make these tools easier for developers to implement, so having an understanding of how they work will significantly improve your react-imgix experience.
Below are some other articles that help explain responsive imagery, and how it can work alongside imgix:
This module exports two transpiled versions. If a ES6-module-aware bundler is being used to consume this module, it will pick up an ES6 module version and can perform tree-shaking. If you are not using ES6 modules, you don't have to do anything
Usage
import Imgix from "react-imgix";
// in react component
;
Examples
Basic Use Case
For simply using as you would use an
, react-imgix can be used as follows:
import Imgix from "react-imgix";
;
Please note:
100vw
is an appropriate
sizes
value for a full-bleed image. If your image is not full-bleed, you should use a different value for
Since imgix can generate as many derivative resolutions as needed, react-imgix calculates them programmatically, using the dimensions you specify. All of this information has been placed into the srcset and sizes attributes.
Width and height known: If the width and height are known beforehand, it is recommended that they are set explicitly:
import Imgix from "react-imgix";
;
Server-Side Rendering
React-imgix also works well on the server. Since react-imgix uses
srcset
and
sizes
, it allows the browser to render the correctly sized image immediately after the page has loaded.
import Imgix from "react-imgix";
;
If the width and height are known beforehand, it is recommended that they are set explicitly:
import Imgix from "react-imgix";
;
Flexible Image Rendering
This component acts dynamically by default. The component will leverage
srcset
and
sizes
to render the right size image for its container. This is an example of this responsive behaviour.
sizes
should be set properly for this to work well, and some styling should be used to set the size of the component rendered. Without
sizes
and correct styling the image might render at full-size.
Aspect Ratio: A developer can pass a desired aspect ratio, which will be used when
generating srcsets to resize and crop your image as specified. For the
ar
parameter to take effect, ensure that the
fit
parameter is set to
crop
.
The aspect ratio is specified in the format
width:height
. Either dimension can be an integer or a float. All of the following are valid: 16:9, 5:1, 1.92:1, 1:1.67.
Fixed Image Rendering (i.e. non-flexible)
If the fluid, dynamic nature explained above is not desired, the width and height can be set explicitly.
import Imgix from "react-imgix";
;
Fixed image rendering will automatically append a variable
q
parameter mapped to each
dpr
parameter when generating a srcset. This technique is commonly used to compensate for the increased filesize of high-DPR images. Since high-DPR images are displayed at a higher pixel density on devices, image quality can be lowered to reduce overall filesize without sacrificing perceived visual quality. For more information and examples of this technique in action, see this blog post.
This behavior will respect any overriding
q
value passed in via
imgixParams
and can be disabled altogether with the boolean property
Images can be rendered as a background behind children by using
. The component will measure the natural size of the container as determined by the CSS on the page, and will render an optimal image for those dimensions.
// In Component (React)
import { Background } from 'react-imgix'
Blog Title
This component shares a lot of props that are used in the main component, such as
imgixParams
, and
htmlAttributes
.
As the component has to measure the element in the DOM, it will mount it first and then re-render with an image as the background image. Thus, this technique doesn't work very well with server rendering. If you'd like for this to work well with server rendering, you'll have to set a width and height manually.
Set width and height:
Setting the width and/or height explicitly is recommended if you already know these beforehand. This will save the component from having to do two render passes, and it will render a background image immediately.
A warning is displayed when no fallback image is passed. This warning can be disabled in special circumstances. To disable this warning, look in the warnings section.
ImgixProvider Component
The
Higher Order Component (HOC), makes its props available to any nested component in your React application.
For example, by rendering
at the top level of your application with
imgixParams
defined, all your components will have access to the same
imgixParams
.
import React from "react";
import Imgix, { ImgixProvider } from "react-imgix";
import HomePage from "./components/HomePage";
function App() {
return (
{/* ... */}
);
}
export default App;
So that the generated HTML looks something like
You can take advantage of this behavior to use partial URLs with the
prop on the Provider, it can be made accessible to all nested components.
// inside App.jsx
{
/*... */
}
{/* ... */}s
;
{
/*... */
}
Both the
components above will access to the
domain
prop from the provider and have their relative
src
paths resolve to the same domain. So that the generated HTML looks something like:
The props that
makes accessible can also be overridden by components. Any prop defined on the component will override the value set by the Provider.
// inside App.jsx
{
/*... */
}
{/* ... */}s
;
{
/*... */
}
So that the generated HTML looks something like this
To remove a shared prop from an
component, the same prop can be set to
undefined
on the component itself.
// inside App.jsx
{
/*... */
}
{/* ... */}s
;
{
/*... */
}
So that the generated HTML looks something like this:
You can nest
ImgixProvider
components to ensure that different consumers have different props.
For example to give
Imgix
components different props from
Picture
components, you can nest an
ImgixProvider
inside of another one.
The nested Provider will change the Context for the
Picture
component, essentially removing their access to the shared props provided by the root
ImgixProvider
.
import React from 'react'
import Imgix, { ImgixProvider, Picture, Source } from "react-imgix";
export default function simpleImage() {
return (
{/* there props will be accessible to all the imgix components */}
{/* imgixParams prop is no longer defined here */}
)
}
Advanced Examples
General Advanced Usage
Although imgix is open to feature suggestions, we might not accept the feature if it is a very specific use case. The features below are examples of what we consider general advanced use cases. Our target here is to support 95% of all the usages of normal
img
,
picture
, and
source
elements.
If your desired feature falls outside this percentage, do not worry! You will probably still be able to achieve your feature with react-imgix's more powerful API:
buildURL
.
This library exposes a pure function,
buildURL
, for generating full imgix URLs given a base URL and some parameters.
This library allows the developer to pass any attribute they like to the underlying DOM element with
htmlAttributes
.
For example, if the the developer would like to attach a custom
onLoad
callback to an
img
component:
handleImgOnLoad,
}}
/>
Lazy Loading
If you'd like to lazy load images, we recommend using lazysizes. In order to use react-imgix with lazysizes, you can simply tell it to generate lazysizes-compatible attributes instead of the standard
src
,
srcset
, and
sizes
by changing some configuration settings:
The same configuration is available for
components
NB: It is recommended to use the attribute change plugin in order to capture changes in the data-* attributes. Without this, changing the props to this library will have no effect on the rendered image.
Low Quality Image Placeholder Technique (LQIP)
If you'd like to use LQIP images, like before, we recommend using lazysizes. In order to use react-imgix with lazysizes, you can simply tell it to generate lazysizes-compatible attributes instead of the standard
src
,
srcset
, and
sizes
by changing some configuration settings, and placing the fallback image src in the htmlAttributes:
NB: If the props of the image are changed after the first load, the low quality image will replace the high quality image. In this case, the
src
attribute may have to be set by modifying the DOM directly, or the lazysizes API may have to be called manually after the props are changed. In any case, this behaviour is not supported by the library maintainers, so use at your own risk.
Attaching Ref to DOM Elements
A
ref
passed to react-imgix using will attach the ref to the Imgix instance, rather than the DOM element. It is possible to attach a ref to the DOM element that is rendered using
htmlAttributes
:
This works for Source and Picture elements as well.
Props
Shared Props (Imgix, Source)
These props are shared among Imgix and Source Components
src :: string, required
Usually in the form:
https://[your_domain].imgix.net/[image]
. Don't include any parameters.
domain :: string, optional
Required only when using partial paths as
src
prop for a component. IE, if
src
is
"/images/myImage.jpg"
, then the
domain
prop needs to be defined.
For example:
imgixParams :: object
Imgix params to add to the image
src
.
For example:
sizes :: string
Specified the developer's expected size of the image element when rendered on the page. Similar to width. E.g.
Disable generation of variable width src sets to enable responsiveness.
disableLibraryParam :: bool
By default this component adds a parameter to the generated url to help imgix with analytics and support for this library. This can be disabled by setting this prop to
true
.
htmlAttributes :: object
Any other attributes to add to the html node (example:
alt
,
data-*
,
className
).
onMounted :: func
Called on
componentDidMount
with the mounted DOM node as an argument.
attributeConfig :: object
Allows the src, srcset, and sizes attributes to be remapped to different HTML attributes. For example:
Allows customizing the behavior of the srcset generation. Valid options are
widths
,
widthTolerance
,
minWidth
, and
maxWidth
. See @imgix/js-core for documentation of these options.
Picture Props
className :: string
className
applied to top level component. To set
className
on the image itself see
htmlAttributes
.
onMounted :: func
Called on
componentDidMount
with the mounted DOM node as an argument.
htmlAttributes :: object
Any other attributes to add to the html node (example:
alt
,
data-*
,
className
).
Background Props
src :: string, required
Usually in the form:
https://[your_domain].imgix.net/[image]
. Don't include any parameters.
imgixParams :: object
Imgix params to add to the image
src
. This is also how width and height can be explicitly set. For more information about this, see the "Background" section above.
For example:
className :: string
className
applied to top level component. To set
className
on the image itself see
htmlAttributes
.
disableLibraryParam :: bool
By default this component adds a parameter to the generated url to help imgix with analytics and support for this library. This can be disabled by setting this prop to
true
.
htmlAttributes :: object
Any other attributes to add to the html node (example:
alt
,
data-*
,
className
).
Global Configuration
Warnings
This library triggers some warnings under certain situations to try aid developers in upgrading or to fail-fast. These can sometimes be incorrect due to the difficulty in detecting error situations. This is annoying, and so there is a way to turn them off. This is not recommended for beginners, but if you are using custom components or other advanced features, it is likely you will have to turn them off.
Warnings can be turned off with the public config API,
PublicConfigAPI
, which is exported at the top-level.
// in init script/application startup
import { PublicConfigAPI } from "react-imgix";
PublicConfigAPI.disableWarning('');
//... rest of app startup
React.render(...);
Warnings can also be enabled with
PublicConfigAPI.enableWarning('')
The warnings available are:
|
warningName
| Description |
| -------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| fallbackImage | Triggered when there is no
or at the end of the children when using
. A fallback image is crucial to ensure the image renders correctly when the browser cannot match against the sources provided |
| sizesAttribute | This library requires a
sizes
prop to be passed so that the images can render responsively. This should only turned off in very special circumstances. |
Upgrade Guides
8.x to 9.0
This release brings the react-imgix API more in-line with that of imgix's rendering service.
The largest change users will notice is that this project's component will no longer generate a default
fit=crop
parameter. The original intention behind this was that generated images would maintain aspect ratio when at least one of the dimensions were specified. However, the default imgix API behavior sets
, which is now reflected in this project.
Although this may not cause breaking changes for all users, it can result in unusual rendered image behavior in some cases. As such, we would rather err on the side of caution and provide users the ability to opt in to these changes via a major release.
If you are currently relying on the default generation of
fit=crop
when rendering images, you will now have to manually specify it when invoking the component:
The other major change relates to how the component determines an image's aspect ratio. Instead of appending a calculated height
. Luckily, the interface for specifying an aspect ratio is no different from before. However, users will have to pass in the
fit=crop
parameter in order for it to take effect:
7.x to 8.0
This is a very large update to this library with a lot of breaking changes. We apologise for any issues this may cause, and we have tried to reduce the number of breaking changes. We have also worked to batch up all these changes into one release to reduce its impacts. We do not plan on making breaking changes for a while after this, and will be focussed on adding features.
The largest change in this major version bump is the move to width-based
srcSet
and
sizes
for responsiveness. This has a host of benefits, including better server rendering, better responsiveness, less potential for bugs, and performance improvements. This does mean that the old fitting-to-container-size behaviour has been removed. If this is necessary, an example of how this can be achieved can be found here
To upgrade to version 8, the following changes should be made.
See Picture support for more information.
<!-- prettier-ignore-end -->
Remove all usage of
type='bg'
as it is no longer supported. It was decided that it was too hard to implement this feature consistently. If you would still like to use this feature, please give this issue a thumbs up: https://github.com/imgix/react-imgix/issues/160 If we get enough requests for this, we will re-implement it.
Remove props
aggressiveLoad
,
component
,
fluid
,
precision
as they are no longer used.
Change all usages of
defaultHeight
and
defaultWidth
to
width
and
height
props.
Rename
generateSrcSet
to
disableSrcSet
and invert the value passed down as the prop's value. i.e.
when appropriate. If you want to provide a fully-responsive experience for these browsers, react-imgix works great alongside Picturefill!
We support the latest version of Google Chrome (which automatically updates whenever it detects that a new version of the browser is available). We also support the current and previous major releases of desktop Firefox, Internet Explorer, and Safari on a rolling basis. Mobile support is tested on the most recent minor version of the current and previous major release for the default browser on iOS and Android (e.g., iOS 9.2 and 8.4). Each time a new version is released, we begin supporting that version and stop supporting the third most recent version.
This browser support is made possible by the great support from BrowserStack.
Contributors
Thanks goes to these wonderful people (emoji key):
This project follows the all-contributors specification. Contributions of any kind welcome, but please review the contribution guidelines before getting started!
Meta
React-imgix was originally created by Frederick Fogerty. It's licensed under the ISC license (see the license file for more info).
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imgix/ react-imgix
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![http://yourdomain.imgix.net/image.png"](https://yourdomain.imgix.net/image.png"){kind=link}
