How to Add Alt Text to Images in WordPress

If you landed here because a scanner, an SEO plugin, or a tool like imagecheck.tools just told you your images are missing descriptions, you're in the right place. This article covers how to add alt text to images in WordPress: exactly where the field lives, how to fill it in for new uploads, and why fixing it in one spot doesn't always fix it everywhere. If you're also wondering what to actually type into that field, our alt text guide covers that side of things.

Alt text (short for "alternative text") is the written description attached to an image. Screen readers speak it out loud for visitors who can't see the picture. Google uses it to understand and index images in Google Images search. Browsers show it as a placeholder if the image file fails to load.

One small field, three different jobs, which is part of why it's worth getting right. If you want the fuller picture of how alt text feeds into Google Images and the rest of the ranking signals, our image SEO guide covers file names, alt text and the other pieces together.

How to Add Alt Text to Images in WordPress, Step by Step

Before touching any field, it helps to know that WordPress doesn't store alt text in just one place. There are three separate spots where an image can carry alt text, and they don't automatically stay in sync with each other. Each record has to be updated on its own.

Where alt text lives in WordPress

Here's the quick map before you start clicking around:

• The Media Library. Every uploaded file has an attachment record, and that record has its own Alt Text field. This is documented as an attachment-level property, separate from anything stored inside a post's content, according to WordPress's own Media Library screen documentation.
• The Block Editor's Image block. When you place an image inside a post or page, that specific instance can carry its own alt text, independent of the Media Library record.
• The featured image. This is a separate attachment slot from anything inside the post body, and it needs its own alt text set (WordPress also exempts it from lazy loading, since it is usually the largest image on the page).
• The Classic Editor's Attachment Details dialog. If your site still runs the older editor, alt text is set here on a per-instance basis, similar to the Block Editor.

None of these four locations pushes an update to the others automatically, which explains most of the confusion people run into.

Add alt text through the Media Library

This is the fastest way to set a default description that future image insertions will pick up.

1. In your WordPress dashboard, go to Media > Library. You should see a grid or list of every file you've uploaded. If the screen is blank, you likely haven't uploaded anything yet, or you're logged into the wrong site.
2. Click on the image you want to edit. A panel should slide open on the right side showing the file details: title, caption, description, and an Alt Text field near the top. If nothing opens, try clicking directly on the thumbnail rather than the filename text below it.
3. Click into the Alt Text field and type a short, specific description of what's in the image. You should see your text appear as you type, with no save button required for this panel; WordPress saves it automatically when you click elsewhere or close the panel.
4. Close the panel and reopen the same image to confirm your text is still there. If the field looks empty again, check that you're editing the actual file and not a duplicate copy accidentally uploaded twice.

One thing worth knowing up front: this only sets the default alt text WordPress will suggest the next time you insert this file into a new post or page. It will not retroactively change images already placed in posts you published earlier.

Add or edit alt text in the Block Editor

This is where you'll set alt text for a specific instance of an image inside a specific post or page.

1. Open the post or page in the Block Editor and click directly on the image you want to fix. A toolbar should appear above the image, and a settings panel should open on the right labeled with the block type. If no panel appears, click the small gear icon in the top-right corner of the editor to toggle it open.
2. In the right-hand panel, find the Content tab and look for the Alt text (alternative text) field. Type your description directly into it. You should see the text save as you move to another field; there's no separate save step for this panel, though you'll still need to update and publish the post itself for the change to go live.
3. If the image is purely decorative (a divider, a background flourish, nothing that conveys information), check the Mark as decorative checkbox instead of writing alt text. This tells screen readers to skip the image entirely rather than announce an empty or unhelpful description.
4. Alternatively, click the image itself, choose the pencil (edit) icon to open the crop and media editor, and switch to the Details tab. You should find the same Alt Text field there, useful if you're already inside the editor for a crop or resize.

Here's the fact that trips up more people than anything else in this whole process. WordPress's own Image block documentation states it plainly: alt text added in the block settings "only applies to the image on that specific page or post," while alt text added in the Media Library "sets the default alt text when you insert the image elsewhere" (WordPress.org, Image block documentation, updated August 2026). In plain terms, editing one doesn't touch the other.

Don't forget the featured image

Featured images are easy to miss, they live in a sidebar panel and often get set once during publishing and never revisited.

1. While editing a post or page, look in the right-hand sidebar for a section called Featured Image, usually near the bottom below Categories and Tags. If you don't see it, click the Post tab at the top of the panel first; the Block tab hides this section.
2. Click on the thumbnail itself, not just the surrounding text. This should open the Media Library selector or, if an image is already set, take you to a larger preview with an edit option.
3. From there, click the image thumbnail again or look for an Edit Image link, which should take you to the same Attachment Details view used elsewhere in the Media Library, complete with its Alt Text field.
4. Enter your description, close the panel, and refresh the post editor to confirm the field held onto your text. If it reverts to blank, you may be editing a different size variant of the same image, only the original attachment record carries the alt text that themes actually read.

Classic Editor, if you still use it

If your site still runs the Classic Editor, either by choice or through the Classic Editor plugin, the field is in a familiar place.

1. Click on the image inside your post to select it, then click the pencil icon that appears to open the Image Details dialog.
2. Find the Alternative Text field near the top of the dialog and type your description into it.
3. Click Update at the bottom of the dialog to apply the change to that image instance, then update and republish the post itself. If your changes don't appear on the live page, clear any caching plugin you have active before assuming the edit failed.

Does changing alt text in the Media Library update old posts?

No. Once an image is placed inside a post or page, whatever alt text was attached at that moment gets written into that specific piece of content. Editing the Media Library afterward changes the master record for future use, but it does not reach back into posts where the image has already been inserted.

WordPress's documentation confirms this directly rather than leaving it to guesswork. On its Image block page, updated in August 2026, it states that Media Library edits set "the default alt text when you insert the image elsewhere," while per-post edits apply only to that one instance. That word "elsewhere" means future insertions, not existing ones.

This confusion is common: someone updates the Media Library, assumes every use of that image across the site inherited the new text, and only notices the mismatch when a screen reader user or an audit tool flags the old post. The practical fix, if you don't want to retype the description by hand, is to open the old post, click the image, choose Replace, and re-select the same file from the Media Library so the current default attaches fresh.

So if you need to fix alt text on images already sitting in published posts, you have two realistic options. Manually reopen each post, click into each affected image, and re-set the alt text directly in the Block Editor's Content tab (the fastest route if you're only fixing a handful of images). Or, for larger sites with the problem spread across dozens or hundreds of posts, look at a bulk-editing plugin, which is exactly what the next section covers.

Can you add alt text in bulk in WordPress?

Core WordPress has no native bulk editor for alt text. You're working image by image unless you bring in a plugin.

For WordPress alt text bulk editing, plugins generally fall into two categories, and it's worth understanding the difference before installing either:

• Manual bulk editors. These add a spreadsheet-style screen to your dashboard where you can see every image's current alt text side by side and type in new descriptions yourself, faster than clicking through the Media Library one file at a time, but still requiring you to write every description.
• AI auto-generators. These scan your image files and generate suggested alt text automatically using image recognition, often processing dozens or hundreds of images in a few minutes.

The speed of the AI category is genuinely appealing. Marketing copy for these plugins likes to cite numbers like fixing 160 images in five minutes, and that efficiency gain is real, but it usually leaves out whether anyone reviewed the output before it went live. Automated image recognition is decent at naming obvious objects (a dog, a laptop, a sunset) and considerably worse at anything specific to your business: a product's exact model name, the purpose of a chart, or why a screenshot matters in context. Treat AI-generated alt text as a first draft, not a finished answer, and spot-check a sample before trusting a full batch.

Before choosing generated text over silence, it's worth deciding whether an image needs a description at all. The W3C Web Accessibility Initiative's guide to decorative images lays out exactly that distinction: images that add information need real alt text, and images that are purely visual flourish should get an empty alt="" instead of being described or skipped entirely, and it's genuinely worth five minutes if you're unsure which category an image falls into.

Does WordPress add alt text automatically?

No, not on its own. Core WordPress does not scan uploaded images or generate any description automatically; every image you upload starts with a blank Alt Text field unless you fill it in yourself. Any automatic or AI-driven alt text generation you've seen mentioned comes from a third-party plugin installed and configured separately, never from WordPress out of the box.

Worth a brief mention: WordPress 6.9 introduced the Abilities API, a system that lets plugins register standardized capabilities that automation tools and AI agents can call directly in a machine-readable format (Make WordPress Core, November 2025). It's early infrastructure rather than something you'll use directly today, but it points toward tasks like alt text generation getting more tightly integrated into core workflows over time.

Check your work

Once you've added or fixed alt text, the last step is confirming it actually made it onto the live page, not just into the editor or the Media Library panel. This matters because, as the sections above cover, an edit in one location doesn't guarantee it shows up everywhere the image appears.

Run the page through this site's free alt text checker by pasting the live URL in. It pulls every image on the page and flags which ones are missing alt text, which have generic placeholders like "image1" or a bare filename, and which are marked decorative, giving you a clear list of what's actually live rather than what you think you saved. A clean report confirms your alt text is present and reasonably specific, not that it's the best possible description, that judgment call is still yours, and WordPress's documentation on inserting images is a reasonable reference for how the pieces fit together. If you want a closer look at what a full site-wide audit catches beyond a single WordPress post, our guide to checking alt text on a website walks through the process end to end.

Frequently Asked Questions

Where do I add alt text in WordPress?

You can add alt text in four places: the Media Library's Alt Text field (which sets a default for future insertions), the Block Editor's Image block Content tab (which applies only to that specific post), the featured image's own attachment details, and, if your site still uses it, the Classic Editor's Image Details dialog. Each location is separate and doesn't automatically update the others.

Does changing alt text in the media library update old posts?

No. Editing the Media Library changes the default alt text used the next time you insert that image somewhere new, but it does not retroactively change images already placed inside published posts. WordPress's own documentation confirms this directly: block-level alt text "only applies to the image on that specific page or post." To fix an image already published, open that specific post and edit the alt text in the Block Editor, or re-select the image from the Media Library to force it to pick up the current default.

Can I add alt text in bulk in WordPress?

Not with core WordPress alone, since there's no native bulk editor for alt text. You'll need a plugin, and they generally split into manual bulk editors (spreadsheet-style screens where you type every description yourself) and AI auto-generators (which suggest text automatically based on image recognition). AI-generated suggestions are worth a manual review pass before you trust them across your whole site, since accuracy varies a lot by image type.

Does WordPress add alt text automatically?

No, core WordPress leaves the Alt Text field blank on every upload by default. Any automatic alt text you've encountered comes from a third-party plugin that was installed and configured separately, not from WordPress itself.