Summary
The Alt Text Checker reads every img tag of a page, including lazy-loaded images, and checks its alt attribute. It flags missing alt attributes, file names used as alt, generic words such as "image", alt texts over 125 characters, the same alt repeated on several images, and linked images without any text. It also counts the images without width and height, a cause of layout shift.
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The alt text describes an image for those who cannot see it: screen readers, Google Images and the AI assistants that read the HTML. It is also the anchor text of an image used as a link. A good alt says in one short sentence what the image shows.
What the checker flags
- No alt attribute: the image says nothing, and some screen readers read the file name.
- File name or generic word: "IMG_2034.jpg" or "photo" describes nothing.
- Linked image without text: its alt becomes the anchor, it must describe the target page.
- Too long or repeated: keep it under 125 characters, one description per image.
Writing a good alt text
- Describe what a visitor sees, in the language of the page: "Oak chair, front view".
- Add the keyword only when it really describes the image.
- Write alt="" for purely decorative images, so screen readers skip them.
- Give every image a width and a height to avoid layout shift.
To lighten your images before publishing, use the image compressor. For the other image signals, see image optimization and Core Web Vitals.
