HTML <img> Tag

The HTML <img> tag is used for embedding images into an HTML document.

Before you use the <img> tag, you need to ensure that the image exists on the internet. You then reference the location of that image when using the <img> tag.

Syntax

The <img> tag is written as <img src="" alt=""> (no end tag) with the image URL inserted between the double quotes of the src attribute.

The srcset attribute can also be used in order to specify different images to use in different situations (e.g. high-resolution displays, small monitors, etc). The value of the alt attribute appears if the image cannot be loaded.

The alt attribute provides alternative text for users who are unable to view the image. Some reasons why users can't view the image might include having a slow Internet connection, they are vision impaired and are using text-to-speech software, the image won't load for some reason, etc. Note that the alt attribute is a required attribute.

Like this:

You can also provide the image dimensions using the width and height attributes.

Or you can provide the image dimensions using CSS.

Examples

Basic tag usage

Using width and height

You can use the width and height attributes to provide the dimensions for the image.

In this example, we'll scale the image to be smaller (for demonstration purposes), however, this is not recommended. It's better to scale the image using image-editing software first (i.e. before it's uploaded to the internet) - so that it is the correct size to start with. Doing this reduces the file size. Scaling it using HTML does not reduce the file size - it uses the same (larger) file and simply resizes it in the browser.

Responsive Design

If your website needs to be displayed on multiple sized screens (eg, mobiles, tablets, desktops, laptops, etc) you may find that your images are too large for some devices. This will be particularly true if you use the width and height attributes to set the dimensions of a large image.

Here are two ways of dealing with this situation.

CSS

One trick is to use the CSS max-width property to set a maximum width for the image of 100%. By specifying a maximum width, you are not explicitly setting the actual width. You are simply telling the browser not to go any bigger than the width that you specify - 100%. In this case, the browser should still reduce the size of the image if 100% is too big for the screen.

Like this:

The srcset & sizes Attributes

The srcset and sizes attributes were introduced in HTML5 in order to deal with the issue of multiple sized screens and resolutions.

It goes a step further than a pure CSS solution, because it allows you to specify which images to use in different situations (e.g., high-resolution displays, small monitors, etc).

The srcset Attribute

The srcset attribute accepts a comma-separated list of URLs, optionally combined with either a width descriptor or a pixel-density descriptor. Each URL would normally represent the same image but at a different size or cropping.

Here's an example of what that might look like when using width descriptors:

And here's an example that uses pixel density descriptors:

You should still use the standard src attribute to cater for user agents that don't support the srcset attribute. In fact, the HTML specification states that you must include the src attribute when using the <img> tag.

The sizes Attribute

The sizes attribute allows you to specify different image sizes for different page layouts.

Example:

You can use media queries to specify a list of width values to use, depending on the space available for the image.

Example:

Linked Image

You can link your image to another web page by nesting it inside the <a> tag.

Like this:

Image Maps

You can use the <img> tag along with the <area> and <map> tags to create an image map.

Image maps enables one image to link to multiple pages. You can specify different shapes for the "hotspot" area too.

The following example demonstrates this (click on each country to see where the link goes). For more information on image maps, see the <map> tag.

Attributes

Attributes can be added to an HTML element to provide more information about how the element should appear or behave.

The <img> element accepts the following attributes.

AttributeDescription
altAlternate text. This specifies text to be used in case the browser/user agent can't render the image.
srcURL of the image.
srcset

Comma-separated list of images to use in different situations (e.g., high-resolution displays, small monitors, etc).

Each image URL can be optionally followed by a whitespace and a descriptor. The descriptor, if any, can be one of the following:

  • A width descriptor (a positive integer directly followed by w). The width descriptor is divided by the source size given in the sizes attribute to calculate the effective pixel density.
  • A pixel density descriptor (a positive floating point number directly followed by x).
sizesImage sizes between breakpoints.
crossoriginThis attribute is a CORS settings attribute. CORS stands for Cross-Origin Resource Sharing. The purpose of the crossorigin attribute is to allow you to configure the CORS requests for the element's fetched data. The values for the crossorigin attribute are enumerated.

Possible values:

ValueDescription
anonymousCross-origin CORS requests for the element will not have the credentials flag set. In other words, there will be no exchange of user credentials via cookies, client-side SSL certificates or HTTP authentication.
use-credentialsCross-origin CORS requests for the element will have the credentials flag set.

If this attribute is not specified, CORS is not used at all.

An invalid keyword and an empty string will be handled as the anonymous value.

ismapFor image maps. See HTML map tag
usemapFor image maps. See HTML map tag
widthSpecifies the width of the image.
heightSpecifies the height of the image.
referrerpolicyReferrer policy for fetches initiated by the element.
longdescA url that provides a link to an expanded description of the image.
decoding

Indicates the preferred method to decode this image. The attribute, if present, must be an image decoding hint. This attribute's missing value default and invalid value default are both the auto state.

loadingThis is a lazy loading attribute. Its purpose is to indicate the policy for loading images that are outside the viewport.

Possible values:

Keyword Description
lazy Used to defer fetching a resource until some conditions are met.
eager Used to fetch a resource immediately; the default state.

Global Attributes

The following attributes are standard across all HTML elements. Therefore, you can use these attributes with the <img> tag , as well as with all other HTML tags.

For a full explanation of these attributes, see HTML 5 global attributes.

Event Handlers

Event handler content attributes enable you to invoke a script from within your HTML. The script is invoked when a certain "event" occurs. Each event handler content attribute deals with a different event.

Most event handler content attributes can be used on all HTML elements, but some event handlers have specific rules around when they can be used and which elements they are applicable to.

For more detail, see HTML event handler content attributes.