AI Alt Text Generator

Paste an image URL and get three AI-generated alt-text suggestions, one for each common use case: informative, decorative, and functional. Pick the one that matches how the image is used on your page, then review and edit before shipping.

This tool is informational and is not legal advice. Always have a human review AI-generated alt text before publishing.

How to choose between informative, decorative, and functional

Alt text is not one-size-fits-all. The right alt text depends on why the image is on the page in the first place. The W3C describes roughly four to seven categories of images, but for most websites, three buckets cover almost every case: informative, decorative, and functional. This tool gives you a draft for each of the three so you can pick the one that matches how the image is actually used in your layout.

Informative

Use informative alt text when the image carries meaning that is not already in the surrounding text. A product photo on a category page, a headshot in a team bio, an editorial photo at the top of a news article, or a chart embedded in a blog post are all informative images. The alt text should describe the meaningful content of the image in plain language. A good informative alt for a product photo might be "Black leather messenger bag with brass buckles, front view" rather than just "bag" or, worse, the filename.

Decorative

Decorative images are there for visual polish. Background textures, repeating patterns, divider flourishes, and stock photos that purely echo nearby text are usually decorative. The right alt text for a decorative image is an empty string — alt="". That tells screen readers to skip the image. Critically, you must still include the alt attribute. Omitting it entirely causes some screen readers to announce the filename instead, which is almost never what you want.

Functional

Functional images live inside links or buttons and represent an action. An icon-only submit button, a magnifying-glass search icon, a shopping-cart icon in the header, a social share icon — these are functional. The alt text should describe the action, not the icon. "Submit search" is better than "magnifying glass." "Open shopping cart" is better than "cart icon." If the image is inside an <a> or <button>, ask yourself what the click does, and write that.

Why placeholder and filename alt text fails screen reader users

The most common alt-text failures are not blank — they are bad. Screen reader users routinely hear alt text like "image," "picture," "IMG_4827.jpg," or "hero-banner-v3-final-final.png." That kind of alt text is worse than no alt text because it interrupts the reading flow and announces nothing useful. Auto-generated alt that just says "photo" on every product card is the same problem at scale. If you ship a placeholder, ship an empty alt instead so the screen reader simply moves on.

Common mistakes to avoid

• Using alt="image" or alt="picture" on real images. Screen readers already announce the element as an image.
• Repeating the caption or the surrounding heading verbatim in the alt. The screen reader will then read the same content twice.
• Starting alt text with "Image of..." or "Photo of..." This is redundant. Lead with the subject.
• Hiding alt that does not match what is visible. If the visible image and the alt text describe different things, sighted and non-sighted users get different versions of your page — which breaks trust and can violate WCAG 1.1.1.
• Cramming SEO keywords into alt text. Alt is for accessibility, not keyword stuffing. Stuffed alt actually hurts ranking signals because it lowers content quality.
• Forgetting the alt attribute on decorative images. Use alt="", not nothing.

When NOT to use AI for alt text

AI is helpful for first drafts at scale. It is not appropriate for every image. Avoid AI-only alt text in these situations:

• Sensitive or medical images. Patient photos, forensic content, or anything with privacy implications should be described by a human who understands the context.
• Brand-critical images. A homepage hero, an ad creative, or a campaign image often has tone, brand voice, and messaging that AI will flatten. Have your marketing team write the alt.
• Infographics, charts, and screenshots with data. The model may misread numbers or labels. For data-bearing images, write a concise alt and provide a longer accessible description (e.g. via aria-describedby or a nearby data table) authored from the source data.
• Images whose meaning depends on surrounding text. The same product photo in a "new arrivals" section and a "sale" section may need different alt. AI cannot see your page; it only sees the image.

How to test alt text manually

After you write or update alt text, test it. Three quick checks:

1. Screen reader pass. On macOS, turn on VoiceOver (Cmd+F5) and arrow through the page. On Windows, install NVDA (free) and use the down-arrow to move element by element. Listen for filenames, "image," or anything that breaks the flow.
2. Browser dev tools. In Chrome or Firefox, open the Accessibility panel and inspect the image. Confirm the accessible name matches your intended alt and that the role is correct (image vs. button vs. link).
3. Disable images. Use a browser extension to hide images and read the page as text only. If the page still makes sense, your alt text is doing its job.

For a deeper guide to image accessibility patterns, see our image alt-text fix guide. For the underlying WCAG criterion this tool supports, see WCAG 1.1.1 Non-text Content.

Sources

• W3C WAI Images Tutorial (opens in new tab)
• W3C WCAG Understanding 1.1.1 Non-text Content (opens in new tab)