Image alt text checker

What it does

An alt text checker finds every image in a page's HTML and tells you which ones have a problem with their alt attribute. It flags images with no alt at all, alt text that is just a file name such as IMG_4821.jpg, single generic words like "photo" or "logo", text that starts with "image of", very long descriptions and the same alt repeated on several images. It also catches the most serious case: an image that is the only thing inside a link or button but has empty alt, which leaves that link with no name. Images with alt="" outside links are listed as decorative so you can confirm they really are.

How to use it

1. Open the page and view its source (Ctrl+U, or Cmd+Option+U on a Mac).
2. Copy all of it and paste it into the box. A snippet of HTML works too.
3. Read the table. Each row shows the image file, its alt text, a status and a short suggestion.
4. Fix the red rows first, then review the amber ones.
5. Copy the report into a spreadsheet to share with whoever edits the site.

How to read the result

The sample has nine images. The Images stat shows 9, with 1 marked decorative. To fix shows 4 and To review shows 1.

The four to fix are typical. One image has alt="IMG_4821.jpg", which a screen reader reads as a string of letters and numbers. One has no alt attribute at all. One, book-now.png, is the only content of a link and has empty alt, so the link is announced with no name; its alt should say "Book an appointment". The last has alt="photo", which says nothing about the picture.

The one to review starts with "Image of a dentist…". Screen readers already announce that it is an image, so start with what it shows: "Dentist whitening a patient's teeth".

The divider with alt="" is listed as decorative, which is correct. The logo inside the home link, the clinic entrance and the search button all pass, because their alt text says what each image shows or does.

The checker cannot see images, so it cannot judge whether a description is accurate. Read each alt in context and ask what a sighted visitor would take from the image. The W3C's alt text decision tree helps with the harder cases.

Before uploading images, shrink them with the image compressor. Alt text, headings and page structure are all covered in our technical SEO service.