Why alt text matters beyond accessibility alone
The alt attribute on an image tag exists primarily for accessibility: it's what a screen reader announces in place of an image for a visually impaired visitor, and it's what displays as fallback text if an image fails to load for any reason. That alone makes it worth getting right on every meaningful image, but it also plays a secondary role in SEO, since search engines can't visually interpret an image's content the way a person can and rely partly on alt text, along with surrounding context, to understand what an image depicts and how it relates to the page's content — relevant for both general search relevance and for a page's images to be discoverable through image search.
This tool parses a page's HTML with the browser's built-in DOM parser, finds every image tag, and sorts each one into missing (no alt attribute at all, or an empty one), generic (a placeholder-style value like "image" or "photo" that technically satisfies the attribute but conveys nothing about the actual content), or acceptable. It's worth being honest about what "acceptable" means here: this tool checks that alt text exists and isn't one of a handful of obviously generic placeholder words — it cannot verify that the text is actually accurate or well-written, since that requires understanding the image itself, which a text-only client-side tool has no way to do.
Where the filename-based suggestions come from
For each image, this tool also generates a starting suggestion by cleaning up the image's filename: stripping the file extension, replacing hyphens and underscores with spaces, removing stray numbers, and capitalizing the first letter. A file named "blue-running-shoes-side-view.jpg" becomes "Blue running shoes side view" — a reasonable rough draft, assuming the site's filenames are already descriptive. This is explicitly a text-based heuristic, not image recognition; it has no ability to look at the actual pixels of an image and describe what's visually in it, so a filename like "IMG_4821.jpg" will produce an unhelpful, mostly empty suggestion, since there's simply no descriptive information in that filename to work with.
Treat every suggestion here as a starting point to edit, not a finished answer. Good alt text describes what's specifically relevant about the image in the context of the page it's on — a product photo's alt text should typically mention the product and any distinguishing detail visible in that specific image, like a particular color or angle, rather than a generic restatement of the product name already given elsewhere on the page.
A few practical alt text guidelines
Purely decorative images that add no informational value — a background texture, a spacer graphic, a repeated visual flourish — are generally better served with an empty alt attribute (alt="") rather than a forced, meaningless description, since an empty alt tells a screen reader to skip the image entirely rather than announcing something unhelpful. Avoid starting alt text with phrases like "image of" or "picture of," since a screen reader already announces that the element is an image before reading the alt text, making that phrasing redundant. Keep the description reasonably concise — a full sentence or two is usually more than enough — rather than stuffing it with every keyword that might be tangentially related to the page.