Alt text, short for alternative text, is a short description added to images on a website. Its main purpose is to help people who can’t see the image—either because they’re using a screen reader or the image didn’t load properly—understand what it shows.

Think of alt text like a caption you’d say over the phone to describe a photo to a friend. For example, if your image shows a dog playing in the snow, your alt text might be: “Golden retriever puppy running through snow in a park.” Clear and simple.

Alt text serves three key purposes:

1. Accessibility – It helps visually impaired users understand image content using screen readers. This makes your website more inclusive.
2. SEO – Search engines can’t “see” images, but they can read alt text. Descriptive alt text helps your images show up in Google Images, bringing more traffic to your site.
3. Backup Description – If an image fails to load, the alt text is shown in its place, giving users context.

Here’s how to use it:

• Keep it short and descriptive (usually under 125 characters).
• Don’t say “image of” or “picture of”—just describe what it is.
• Use keywords naturally, but avoid keyword stuffing.

Bad alt text: “Image123.jpg”
Good alt text: “Two kids riding bikes on a sunny trail”

Whether you’re blogging, running an online store, or just sharing photos, writing great alt text helps your content reach everyone—and be found more easily online.