amp-img

Usage

The AMP HTML replacement for the normal HTML img tag. With amp-img, AMP provides a powerful replacement.

AMP may choose to delay or prioritize resource loading based on the viewport position, system resources, connection bandwidth, or other factors. The amp-img components allows the runtime to effectively manage image resources this way.

amp-img components, like all externally fetched AMP resources, must be given an explicit size (as in width / height) in advance, so that the aspect ratio can be known without fetching the image. Actual layout behavior is determined by the layout attribute.

In the following example, we display an image that responds to the size of the viewport by setting layout=responsive. The image stretches and shrinks according to the aspect ratio specified by the width and height.

<amp-img
  alt="A view of the sea"
  src="/static/inline-examples/images/sea.jpg"
  width="900"
  height="675"
  layout="responsive"
>
</amp-img>

If the resource requested by the amp-img component fails to load, the space will be blank unless a fallback child is provided. A fallback is only executed on the initial layout and subsequent src changes after the fact (through resize + srcset for example) will not have a fallback for performance implications.

Specify a fallback image

In the following example, if the browser cannot load the image, it'll display the fallback image instead (here we're using an inline SVG as fallback):

<amp-img
  alt="Misty road"
  width="550"
  height="368"
  src="image-does-not-exist.jpg"
>
  <amp-img
    alt="Misty road"
    fallback
    width="550"
    height="368"
    src="data:image/svg+xml;base64,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"
  >
  </amp-img>
</amp-img>

A placeholder background color or other visual can be set using CSS selector and style on the element itself.

Additional image features like captions can be implemented with standard HTML (for example, figure and figcaption).

Scale an image up to a maximum width

If you want your image to scale as the window is resized but up to a maximum width (so the image doesn't stretch beyond its width):

1. Set layout=responsive for <amp-img>.
2. On the container of the image, specify the max-width:<max width to display image> CSS attribute. Why on the container? An amp-img element with layout=responsive is a block-level element, whereas, <img> is inline. Alternatively, you could set display: inline-block in your CSS for the amp-img element.

The difference between the responsive and intrinsic layouts

Both the responsive and intrinsic layouts create an image that will scale automatically. The main difference is that the intrinsic layout uses an SVG image as its scaling element. This will make it behave in the same way as a standard HTML image while retaining the benefit of the browser knowing the image size on initial layout. The intrinsic layout will have an intrinsic size and will inflate a floated div until it reaches either the image size defined by the width and height attributes passed to the amp-img (not by the natural size of the image) or a CSS constraint such as max-width. The responsive layout will render 0x0 in a floated div because it takes its size from the parent, which has no natural size when floated.

Set a fixed sized image

If you want your image to display at a fixed size:

1. Set layout=fixed for <amp-img>.
2. Specify the width and height.

Set the aspect ratio

For responsive images, the width and height do not need to match the exact width and height of the amp-img; those values just need to result in the same aspect-ratio.

For example, instead of specifying width="900" and height="675", you can just specify width="1.33" and height="1".

<amp-img
  alt="A view of the sea"
  src="/static/inline-examples/images/sea.jpg"
  width="1.33"
  height="1"
  layout="responsive"
>
</amp-img>

Set multiple source files for different screen resolutions

The srcset attribute should be used to provide different resolutions of the same image, that all have the same aspect ratio. The browser will automatically choose the most appropriate file from srcset based on the screen resolution and width of the user's device.

In contrast, the media attribute shows or hides AMP components, and should be used when designing responsive layouts. The appropriate way to display images with differing aspect ratios is to use multiple <amp-img> components, each with a media attribute that matches the screen widths in which to show each instance.

See the guide on creating responsive AMP pages for more details.

Maintain the aspect ratio for images with unknown dimensions

The AMP layout system requires the aspect ratio of an image in advance before fetching the image; however, in some cases you might not know the image's dimensions. To display images with unknown dimensions and maintain the aspect ratios, combine AMP's fill layout with the object-fit CSS property. For more information, see the How to support images with unknown dimensions example.