Quick answer

Add concise alternative text to informative images, and use alt="" for images that are purely decorative. Do not stuff keywords into alt text or repeat nearby captions. Missing alt text is mainly an accessibility finding, although it can also reduce the useful context available when images cannot be viewed.

What the issue means

The alt attribute gives a text alternative for an image. NOTABIS reports missing-alt when an image element has no alt attribute; it does not report an issue when the attribute is intentionally empty. That distinction matters: an empty alt tells assistive technology that a decorative image can be skipped.

Alt text should describe the image’s function in context, not every pixel. A product image may need the product name, while a decorative divider needs no words.

Why it matters for SEO

Accessible pages are easier to use and maintain. Search systems may use image context, filenames, surrounding text, and alt attributes to understand images, but alt text is not a place for keyword lists or ranking guarantees. The strongest reason to fix missing alt is that some visitors cannot receive the visual information otherwise.

How NOTABIS detects it

The missing-alt rule counts image elements without an alt attribute in the crawled HTML and records the number on the affected page. It does not judge whether existing alt text is accurate, descriptive, too long, or appropriate to the surrounding content.

How to check it yourself

Inspect each image in context. Ask what a visitor needs to know if the image is unavailable. Check whether a nearby caption already provides the information and whether the image is linked, functional, decorative, or part of a chart. Test with images disabled or a screen reader when possible.

How to fix it

Use the simplest accurate alternative:

<img src="team.jpg" alt="The support team at the NOTABIS office">
<img src="divider.svg" alt="">

For functional images, describe the action or destination. For charts, provide the important data in nearby text or a table; a short alt alone may not be enough. For complex product galleries, make each alternative distinct and useful.

Avoid alt="image", filenames, keyword repetition, and descriptions that duplicate a visible caption without adding value.

When it is intentional or does not need fixing

Decorative images should normally have an empty alt attribute, not a missing attribute. CSS background images may not require alt text, but important information should not exist only as a background. An image with a complete adjacent text equivalent may need only a concise label or an empty alt depending on its function.

Related issues

Also review missing image dimensions, legacy image formats, and missing main landmarks.

Run a NOTABIS audit

A NOTABIS audit reports affected pages and the number of images missing an alt attribute, giving you a practical queue for template and content fixes.