Images are a vital part of web content, making pages more engaging and informative. However, for search engines and users with visual impairments, images can be invisible without proper textual descriptions. This is where alternative text (commonly known as alt text or alt tags/attributes) comes in. Alt text is a fundamental aspect of image SEO and web accessibility, providing context and meaning to your visual content.
📷 What Are Alt Tags (Alt Text)?
The alt attribute is part of the HTML <img> tag. It provides a textual alternative for an image if the image cannot be displayed on a user's screen for any reason (e.g., slow connection, error in the src path, or if the user is using a screen reader).
Here’s how it looks in HTML:
<img src="path/to/your/image.jpg" alt="A descriptive explanation of the image content.">For example, for an image of a red apple on a wooden table, a good alt text would be:
<img src="red-apple.png" alt="A shiny red apple resting on a rustic wooden table.">🧠 Why Do Alt Tags Matter?
- Accessibility: This is the primary purpose of alt text. Screen readers use alt text to describe images to visually impaired users, making your content accessible to a wider audience and complying with accessibility guidelines (like WCAG).
- SEO (Search Engine Optimization): Search engines like Google use alt text to understand the content and context of your images. Well-optimized alt text can help your images rank in Google Images search, driving additional traffic to your site. It also contributes to the overall topical relevance of the page.
- Broken Images: If an image fails to load for any reason (e.g., incorrect file path, slow internet connection), the browser will display the alt text in place of the image. This provides users with context about what they're missing.
- Anchor Text for Image Links: If an image is used as a link, the alt text functions as the anchor text for that link, providing SEO value and context to search engines about the linked page.
🛠 How to Write Good Alt Text & Tools to Check:
Writing effective alt text is an art and a science. Here are some best practices:
- Be Descriptive and Specific: Clearly describe what's in the image as accurately as possible. Imagine you're describing it to someone who can't see it.
- Keep it Concise: Aim for under 125 characters if possible. While there's no hard limit, screen readers might truncate very long alt text. Be succinct but informative.
- Use Keywords Naturally: If relevant to the image and your content, include your target keyword or related phrases. However, avoid keyword stuffing; the primary goal is to describe the image.
- Avoid "Image of..." or "Picture of...": It's usually redundant, as screen readers and search engines already know it's an image from the
<img>tag. - Use an Empty Alt Attribute for Decorative Images: If an image is purely decorative and doesn't convey any meaningful content or information (e.g., a background pattern or spacer image), use an empty alt attribute (
alt=""). This tells screen readers to ignore the image. Do not omit the alt attribute entirely, as some screen readers may read the file name instead. - Don't Forget Context: The best alt text often depends on the context of the surrounding content.
You can use several tools to check for missing or problematic alt text:
- Browser Developer Tools: Right-click on an image and select "Inspect" or "Inspect Element" to view the HTML and check the alt attribute.
- Website Crawlers: Tools like Screaming Frog SEO Spider (free version has limits) or Sitebulb can crawl your entire website and report on images missing alt text.
- Our own Alt Tag Checker: Quickly analyze a single page to find images and check their alt text status.
- Browser Extensions: Various SEO or accessibility checker browser extensions can highlight images lacking alt text.
By consistently providing well-written alt text for your images, you enhance user experience for everyone, improve your site's accessibility, and give your SEO a valuable boost. It’s a small effort with significant returns.