amp-img

Introduction

AMP HTML files don't support the normal HTML img tag. With amp-img AMP provides a powerful replacement.

Setup

amp-img is a built-in element and is automatically imported via the AMP runtime.

<script async src="https://cdn.ampproject.org/v0.js"></script>

You can use the amp-bind extension for dynamically changing an image.

<script async custom-element="amp-bind" src="https://cdn.ampproject.org/v0/amp-bind-0.1.js"></script>

Basic usage

A simple responsive image - width and height are used to determine the aspect ratio. Use alt to specify text that can act as an alternative for the image.

<amp-img src="/static/samples/img/amp.jpg" width="1080" height="610" layout="responsive" alt="AMP"></amp-img>

HTML 5.1 provides guidance for creating text to act as an alternative for images.

srcset

Use srcset to specify different images for varying viewport widths and pixel densities (change the width of your browser windows to test it).

<amp-img src="/static/samples/img/amp.jpg" srcset="/static/samples/img/amp.jpg 1080w, /static/samples/img/amp-900.jpg 900w, /static/samples/img/amp-800.jpg 800w,
/static/samples/img/amp-700.jpg 700w, /static/samples/img/amp-600.jpg 600w, /static/samples/img/amp-500.jpg 500w, /static/samples/img/amp-400.jpg 400w,
/static/samples/img/amp-300.jpg 300w, /static/samples/img/amp-200.jpg 200w, /static/samples/img/amp-100.jpg 100w" width="1080" height="610" layout="responsive" alt="AMP"></amp-img>

Offline fallback

amp-img supports AMP's common attributes, which means you can show a fallback in case the image couldn't be loaded. This is great for adding offline support to your AMPs.

offline

<amp-img src="/static/samples/img/does-not-exist.jpg" width="300" height="100" layout="responsive" alt="a non-existent image">
  <div fallback>offline</div>
</amp-img>

No script

If you want to ensure that users with JavaScript disabled can see your images, you can add an additional img element inside a noscript tag. This also makes it possible for webcrawlers without JavaScript runtime to discover your images.

<amp-img src="/static/samples/img/amp.jpg" width="475" height="268" layout="responsive" alt="AMP">
  <noscript>
    <img src="/static/samples/img/amp.jpg" width="475" height="268" alt="AMP">
  </noscript>
</amp-img>

Hiding the loading indicator

Use the noloading attribute to hide the loading indicators on page load. This is recommended for logos and small images/icons.

<amp-img src="/static/samples/img/amp_by_example_logo.svg" width="208" height="40" alt="AMP by Example" noloading></amp-img>

Dynamically changing the src

You can use amp-bind to dynamically change the src URL of an amp-img. Remember to also change the alt if the content/meaning of the image changes.

<amp-img src="https://unsplash.it/300/200/?image=100" width="300" height="200" alt="Example image" [src]="myImageUrl" [alt]="myImageAlt">
</amp-img>
<button on="tap:AMP.setState({ myImageUrl: 'https://unsplash.it/300/200/?image=200', myImageAlt: 'Another example image' })">Change image</button>

Vertically centering an amp-img

Here is a simple approach to vertically center an amp-img using the flex layout (src):

<div class="outer">
   <amp-img class="inner" layout="responsive" src="https://unsplash.it/300/200" width="3" height="2" alt="a vertically centered amp-img">
   </amp-img>
 </div>

...and here is the CSS:

.inner{
  flex-basis: 0;
  -ms-flex-preferred-size: 0;
  -webkit-box-flex: 1;
  -ms-flex-positive: 1;
  flex-grow: 1;
}
.outer {
  height: 320px; /* adjust to your needs */
  display: flex;
  flex-wrap: wrap;
  -webkit-box-align: center;
  -ms-flex-align: center;
  align-items: center;
}

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Written by @sebastianbenz