Alt attribute

What is an alt attribute?

The alt attribute is an HTML element that provides a text description for images on webpages. This attribute is added to image tags to describe the appearance and function of an image. When you add an alt attribute to an image, you're creating alternative text that appears when the image can't be displayed or when someone is using assistive technology. The syntax is straightforward: <img src="image.jpg" alt="Description of the image">. This simple addition to your HTML makes your images more accessible and provides context to both users and search engines about what the image contains.

How do alt attributes work for SEO?

Search engines can't "see" images the way humans do. The alt attribute bridges this gap by telling search engines what your images are about. When search engine crawlers index your site, they read the alt text to understand the image content and context. This helps them properly index the image and associate it with relevant searches. Well-crafted alt text can help your images appear in image search results, potentially driving additional traffic to your site. Alt attributes also contribute to your overall on-page SEO by reinforcing your content's topic and keywords in a natural, contextual way. When your alt text aligns with your page content, it signals topical relevance to search engines.

Why are alt attributes important for accessibility?

Alt attributes are essential for making the web accessible to everyone. Screen readers, which convert digital text to synthesized speech, rely on alt text to describe images to visually impaired users. Without alt attributes, screen readers might skip the image entirely or read out unhelpful file names instead. This creates a frustrating experience and prevents users from accessing potentially important visual information. In many countries, web accessibility is also a legal requirement, making proper alt text implementation necessary for compliance with regulations like the Americans with Disabilities Act (ADA) or the Web Content Accessibility Guidelines (WCAG). By including thoughtful alt text, you ensure that all visitors can fully experience your content.

What makes an effective alt attribute?

An effective alt attribute is concise yet descriptive, typically between 5-15 words. It should accurately convey the image's content and purpose within the context of the page. Be specific about what the image shows rather than using generic descriptions. For example, instead of "dog," use "golden retriever puppy playing with a red ball." If an image contains text, include that text in the alt attribute. For decorative images that don't add meaningful content, you can use an empty alt attribute (alt="") to indicate to screen readers that the image can be skipped. Avoid keyword stuffing in alt text, as this creates a poor user experience and may trigger search engine penalties. The best alt text reads naturally and provides genuine value to someone who cannot see the image.

How do you add alt attributes to your images?

Adding alt attributes is straightforward across most platforms. In HTML, you simply include the alt attribute within the image tag: <img src="filename.jpg" alt="Description of image">. Most content management systems provide dedicated fields for alt text when uploading or inserting images. In WordPress, you'll find the alt text field in the attachment details when adding media to a post. Website builders like Wix and Squarespace also include alt text options in their image settings panels. For e-commerce platforms, product image alt text can often be added through product editing interfaces. When adding alt attributes through these systems, the platform automatically generates the proper HTML code. Remember to add alt text to all meaningful images, including those in headers, buttons, and icons that convey information.