HTML <img> sizes Attribute

HTML <iframe>

HTML <input>

The sizes attribute on an <img> element specifies different image widths.

These widths are tied to browser conditions which helps create responsive images.

Example

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A sizes attribute on an <img> element.
Resizing the browser will adjust the image file that will display.

<img srcset="/img/html/vangogh-sm.jpg 120w,
             /img/html/vangogh.jpg 193w,
             /img/html/vangogh-lg.jpg 278w"
     sizes="(max-width: 710px) 120px,
            (max-width: 991px) 193px,
            278px">

The three images of different size.

Code Explanation

A small image is used with a screen between 0 - 710px. The layout width is 120px.

A medium image is used with a screen between 711px - 991px. The layout width is 193px.

A large image is used with a screen 992px and larger. The layout width is 278px.

See below for a detailed description.

Using sizes

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The srcset and sizes attributes work together to create responsive images.

The srcset attribute points to image URLs.

And sizes specifies image sizes and browser conditions (media queries).

Each size in sizes has the following format: (media-condition) width

media-condition = Media query (e.g max-width: 540px), followed by a space.
width = The width of the available space in pixels (px), em, or viewport (vw).
Multiple sizes are comma-separated. Here is an example:

<img srcset="/img/new-york-sm.jpg 120w,
             /img/new-york-md.jpg 200w,
             /img/new-york-lg.jpg 300w"
     sizes="((min-width: 10em) and (max-width: 20em)) 10em,
            ((min-width: 30em) and (max-width: 40em)) 30em,
             (min-width: 40em) 40em">