Image Alt Text Checker

How to use the image alt text checker

1. Paste a page, a template, or just the image tags.
2. Fix the errors: missing alt and filenames used as descriptions.
3. Check anything marked decorative really is.

About this tool

The advice everyone is given — every image needs alt text — is wrong in a way that matters, and this checker is built around the correction. A decorative image needs an *empty* alt, `alt=""`, so that a screen reader skips it. Missing and empty are different states: with no alt attribute at all, screen readers commonly read the filename aloud, so a spacer announces itself as "divider dash line dot p n g". That is worse than silence, and a blanket rule produces exactly it.

Length is the other misunderstanding. Alt text is announced as one unbroken run with no sentence breaks, so a paragraph of description is exhausting to listen to. Describe what the image conveys in a sentence and put the detail in the page, where everyone benefits rather than only the people who cannot see it.

The rest of the checks are the recurring faults: a filename used as the description, leftover stand-ins such as "Photo", "image of" prefixes that a screen reader has already announced, keyword lists dressed as descriptions, and the same alt text repeated across different images — which usually means one of them is described wrongly.

Missing width and height are flagged too, because that is what causes the page to jump as images load. It is the layout shift Core Web Vitals measures, and it is an accessibility problem as much as a performance one for anyone who has just tapped where a link used to be.

Common uses

• Auditing a page's images before launch.
• Checking alt text a CMS or plugin generated.
• Finding images that will shift the layout as they load.

Frequently asked questions

Should every image have alt text?

Every image needs an alt attribute; a decorative one should have an empty alt so screen readers skip it. Leaving the attribute off means the filename may be read aloud instead.

How long should alt text be?

About a sentence. It is announced as one unbroken run with no sentence breaks, so a paragraph is exhausting — put the detail in the page instead.

Why does missing width and height matter?

Because the page reflows as each image loads. That is the layout shift Core Web Vitals measures, and it moves what someone was about to tap.