What is Alt Text?

Alt text (alternative text) is a brief description of an image that appears if the image doesn't load and is read aloud by screen readers for visually impaired users.

In HTML, it's the text inside the alt attribute of an image tag: <img src="blog-structure.jpg" alt="Diagram showing blog post structure with introduction, body, and conclusion">.

Alt text serves two purposes: it makes your content accessible to people using screen readers, and it helps search engines understand what your images depict.

Why alt text matters

Alt text is both an accessibility requirement and an SEO opportunity. Screen readers rely on alt text to describe images to users who can't see them. Without alt text, these users miss visual information. In many contexts, this is legally required under accessibility standards like WCAG and ADA.

Search engines can't "see" images - they rely on alt text to understand what an image shows. Good alt text helps your images appear in Google Image Search results, which can drive traffic to your blog. If an image doesn't load due to slow connection or broken link, the alt text displays instead.

How to write good alt text

Be specific but brief. Describe what the image shows in under 125 characters. Include keywords naturally if they describe the image, but don't force them. Don't start with "Image of" or "Picture of" - screen readers already announce it's an image.

For decorative images that add no information, use empty alt text: alt="". This tells screen readers to skip the image.

For screenshots, describe what they show. For diagrams, summarize the key point. For charts, describe what the chart shows and its main insight. Avoid keyword stuffing, vague descriptions like "chart," or using filenames as alt text.

Alt text and SEO impact

Alt text alone won't make or break your SEO, but it's one of many signals. Combined with good file names, image optimization, and relevant context, it helps images rank and supports overall page relevance.

More importantly, good alt text makes your content accessible to everyone. That's the primary reason to do it - SEO benefits are secondary. Most blogging platforms make adding alt text easy through image settings when uploading or editing images.