Images missing alt text: how to find and fix them in WordPress

What it looks like in the HTML

Before

<img src="/uploads/IMG_4521.jpg">
<img src="/uploads/pour-over.jpg" alt="">

After

<img src="/uploads/IMG_4521.jpg" alt="Coarsely ground coffee in a glass jar next to a measuring cup">
<img src="/uploads/pour-over.jpg" alt="Pouring cold water over grounds in a mason jar">

Why it matters

Screen readers read the alt text aloud. With none, they either skip the image or read the file name, which is how visitors end up hearing "IMG underscore 4521 dot jpg". Browsers also show alt text when an image fails to load.

For search, alt text is the clearest statement of what an image shows, alongside the file name, caption and surrounding text. It is often the deciding factor in whether an image appears in image search at all. For the full picture, see image alt text and SEO.

Why WordPress images end up without alt text

• Uploads skip the field. The Media Library's Alternative Text field is optional, and most people drag in images without filling it.
• Alt text is copied when the image is inserted. When you add an image block, the block stores the alt text in the post content at that moment. Adding alt text in the Media Library later does not update images already placed in posts, so you have to fix those blocks too.
• WordPress prints an empty alt when none is set. Images with no alt text get alt="", which tells screen readers to skip them. That is right for decorative images and wrong for everything else.
• Page builders, galleries and sliders sometimes use their own image fields or background images that never get alt text.

How to fix it in WordPress

1. Write alt text for new images as you upload. Fill in Alternative Text in the attachment details. Describe what the image shows in the context of the page, in one sentence, without "image of" and without stuffing keywords.
2. Fix images already in posts. In the block editor, select the image block and fill in the Alternative text field in the block settings sidebar. This is the text the page actually prints.
3. Leave decorative images empty on purpose. A divider or a background flourish should keep alt="" so screen readers skip it. Note that this audit counts empty alt as missing, so a page full of decorative images will still be flagged.
4. Use Hydrogen SEO for a backlog. With a connected hydrogenseo.com account, the Generate Alt Text button in the Media Library drafts alt text for one image or a bulk selection, at 1 credit per image. Generate Alt Text with AI on Upload (under Hydrogen SEO → General → Images, off by default) does it for new uploads. Review every result: AI cannot know that the person in the photo is your founder.
5. Use the free fallback carefully. Add Missing ALT Attributes, also under General → Images, fills missing or empty alt attributes when the page is printed, using the Media Library alt text or a template like the post title. It needs no account, but a post title is a weak description, and it also fills decorative images you left empty on purpose.

How to check the fix

View the page source and search for <img, or run [...document.images].filter(i => !i.alt).length in the browser console to count images with no alt text. Purge your cache first. In Hydrogen SEO, the Image alt text part of each post's SEO score reflects images in the content, and the free SEO audit reports how many images on a URL are missing alt text.