How to add alt text to WordPress images in bulk

You can add alt text to hundreds of WordPress images without opening each one by hand, but WordPress itself won't do it for you: core has no bulk alt text editor and no filter for images missing alt text. The workable path is to find the gaps, fix them in the Media Library, and then check the posts where those images are already used.

Where do you edit alt text in WordPress?

Alt text lives in two places: the Media Library and the Image block in the editor. Both end up as the same alt attribute on the page.

• Media Library: open Media, select an image and fill in the Alt Text field of its details panel.
• Image block: select the block in a post or page and edit the alternative text in the block settings.

The difference is scope, and it matters for everything below.

Does changing alt text in the Media Library update images already in my posts?

For images inserted into post content, no. According to the WordPress Image block documentation, alt text in the Media Library sets the default for when you insert the image elsewhere, while a change in the block applies only to that page or post.

Once an image is inside a post, it carries its own copy of the alt text. Editing the library afterward won't touch it.

Images that your theme or a plugin outputs from the Media Library are different. Core's wp_get_attachment_image() reads the current alt text from the attachment, so these pick up changes automatically. Featured images in most themes work this way, but check yours.

In practice: after a bulk fix in the library, open the pages that matter most and check the images inside the content.

How do I find images without alt text?

WordPress doesn't show this out of the box. Your options:

• An SEO crawler. Most report "images missing alt text" per page. It shows the images that are actually displayed, including the ones inside post content that the library can't tell you about.
• An accessibility audit tool. Browser-based and automated checkers flag <img> elements with no alt attribute at all.
• A plugin that adds a column or filter to the Media Library. This shows which attachments have empty alt text, but not where they're used.

The two views differ. A crawler tells you what visitors see, the library tells you what you can fix in one place. Use both.

Why doesn't WordPress have bulk alt text editing?

We couldn't find an official explanation, so treat this as interpretation. Good alt text depends on context – the same photo can need different wording on a product page and in a blog post – and one value applied everywhere is often wrong.

WordPress also deliberately doesn't guess. In 2016 core removed the fallback that built alt text from an image's caption or title, so an image with no alt text stays empty rather than getting a misleading one.

What are your options for adding alt text in bulk?

By hand, with a checklist. Slow, but the best quality. Sort by importance: pages that bring traffic and sales first.

Templates built from existing data. Fast, and risky. Filling alt text from the file name or post title gives you results like:

alt="IMG_4821"
alt="10 tips for choosing a wedding photographer"   (same text on 40 images)

Neither describes the image. Useful alt text says what the image shows, in context:

alt="Bride adjusting her veil in a window-lit hallway"

If you go the template route, fix your file names first – see how descriptive file names affect image search.

AI. The quickest way to get a first draft for every image. It needs supervision, covered next.

What should you watch for with AI-generated alt text?

Three things go wrong most often:

• Generic descriptions. "A person standing in a room" is accurate and useless. The model can't know it's your studio, your product or your client unless you tell it.
• No business context. Without knowing who you are and what the page is about, the text can't match the way your visitors search.
• Saving without review. A wrong description is worse than none, especially for screen reader users, who rely on it.

Also avoid stuffing keywords. Google's image guidance says a keyword list in alt text is a poor experience and may look like spam. Alt text is first of all an accessibility feature; if it's accurate and written for people, search engines benefit as a side effect. For the writing itself, see what alt text does for image SEO.

Which images should have empty alt text?

Purely decorative ones: dividers, flourishes, images that add no information. The W3C guidance on decorative images says to use an empty alt="", not to remove the attribute, because some screen readers then announce the file name.

<img src="divider.png" alt="">

If you're unsure, the W3C alt decision tree walks through the cases. Be careful with images that are links: an empty alt leaves the link without a name.

WordPress 7.1 added a "Mark as decorative" checkbox to the Image block. On older versions, leave the alt text empty. One caution: in current block editors the checkbox discards existing alt text and caption, so don't use it on images you've already described.

Where this gets tedious at scale

Once you're past a few dozen images, the work is finding each one, writing something specific to your business, and checking it. TagDuck for WordPress handles the writing part for images already in your Media Library: it suggests alt text, a description and optionally a caption, plus keywords in the "Image keywords" taxonomy, using context you provide about your business and photos, the keywords that must appear and the output language. Every suggestion can be edited before you accept it, nothing changes until you do, and Undo and "Restore previous" bring back the old text. Your files aren't modified. Like any Media Library change, it doesn't rewrite images already embedded in posts, so the check described above still applies. More at tagduck.io/wordpress; plans and limits are on the pricing page.