Image Alt Text Checker

What this tool does

Image Alt Text Checker parses pasted HTML, finds every <img> element, and checks each one’s alt attribute for common problems: a missing alt attribute entirely, generic placeholder text like "image", alt text that is just the filename, overly long alt text, and empty alt on an image that may not actually be decorative.

Alt text serves two audiences at once: screen reader users, who hear it read aloud in place of an image they cannot see, and search engines, which use it to understand what an image shows since they cannot truly "see" it either. A missing, generic or filename-based alt attribute fails both audiences simultaneously.

This checker parses pasted HTML and examines every <img> tag’s alt attribute against several common problems: missing it entirely, leaving it empty on an image that might be meaningful content rather than decoration, using generic placeholder words like "image" or "photo", leaving the raw filename as the alt text, or writing alt text so long that it becomes tedious for a screen reader user to sit through.

How to use Image Alt Text Checker

1. Paste the HTML containing the <img> tags you want to check.
2. Review the summary counts: images found, missing alt, flagged and clean.
3. Go through each image’s flagged issues one by one.
4. Rewrite the alt text for any flagged image to describe what it actually shows.
5. Re-paste the updated HTML to confirm the issues are resolved.

Tips for better results

• An empty alt="" is correct for genuinely decorative images (a background flourish, a spacer, a repeated icon with adjacent visible text), but is flagged here as worth double-checking, since it is also the most common way a meaningful image accidentally ends up with no real description.
• Good alt text describes what the image shows and why it matters in context, not just restates the surrounding caption or filename; "Hand-stitched tan leather wallet on a wooden table" is useful, "image" or "IMG_4821" is not.
• Keep alt text reasonably concise; a screen reader reads the entire string aloud, so excessively long alt text turns a quick visual glance into a long audio detour for those users.
• If an image is purely decorative and conveys no information, an empty alt="" (not a missing attribute) is the correct, deliberate choice, telling assistive technology to skip it entirely.

Common use cases

• Auditing a page or whole site’s images for missing or poor-quality alt text before an accessibility review.
• Checking that no image’s alt text is just an auto-generated filename left over from a CMS upload.
• Preparing content for an accessibility compliance review (such as WCAG) by catching common alt text problems.
• Improving image SEO by replacing generic or missing alt text with genuinely descriptive text.

Common mistakes to avoid

• Treating every empty alt="" as automatically correct without checking whether that specific image is actually decorative; this is the single most common way meaningful images lose their description.
• Writing alt text that just repeats a visible caption word-for-word instead of describing the image itself, which is redundant for sighted users and unhelpful for those relying on alt text alone.
• Leaving an auto-generated filename (like IMG_4821.JPG) as the alt text, which conveys zero information about what the image actually shows.