Alt text is text associated with an image that some browsers display instead of the image. Search engines use it to identify the content of a page. Adding alt text to images is a great way to give your site an SEO boost and make it more accessible. If you don't manually add alt text to an image, the image's file name will usually serve as alt text.

Alt text is also helpful for assistive screen readers or browsers with images disabled. If a browser can't display the image, the alt text will display instead. For all these reasons, when you add alt text, use short, readable terms that describe the image and relate to your site content.

This guide reviews how to add alt text to your site's images, and images that include alt text automatically.

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Alt text best practices

When writing alt text, remember that you're writing for humans who use assistive screen readers or who've disabled images in their browser. Keep in mind:

• Be descriptive and helpful. How would you describe this image to someone who couldn't see it?
• Keep the text short, typically twelve words or fewer.
• Optimize your text for search by incorporating keywords, but avoid keyword stuffing.
• Write in real sentences; don't use hyphens to separate words.
• You can omit words like "the" and "a," and terms like "photo" or "picture." For example, instead of a picture of a green vase, use green vase.

Image Block

How you add alt text to an Image Block depends on the layout.

Inline layout

Captions added in the Inline layout automatically become alt text for the image. 

To add alt text in the Inline layout and hide the caption:

1. Add the caption text.
2. Click the Content tab in the Image Block editor.
3. Click Caption, then select Off.

Note: In lightboxes, captions always display.

All other layouts

For all other layouts (Poster, Card, Overlap, Collage, and Stack), the captions won't become alt text. Instead, add alt text to the Filename field in the Content tab of the Image Block editor.

Auto layout images

Auto layouts and gallery sections are only supported in version 7.1.

How you add alt text to auto layouts depends on its type. For example, one type includes most auto layouts, which combine text and images. Another type is gallery sections, which primarily showcase images.

Most auto layouts

To add alt text to items in most auto layout sections:

1. While editing a page, hover over the auto layout section and click Edit Content.
2. Click the Content tab.
3. Click the item you want to add alt text.
4. Scroll to Image Alt Text and enter your alt text in the field.
5. Click Back, then click Save.

Gallery sections

A description added to gallery section images automatically becomes alt text and the caption for the image. 

Gallery Page images

Gallery Pages are only supported in version 7.0.

To add alt text to an image in a Gallery Page:

1. Click the Gallery Page in the Pages panel.
2. Find the image to edit, hover over it, and click .

3. Add alt text in the Image Title field. If you don't add an image title, text in the description field becomes alt text.
4. Click Save.

Gallery Block images

In version 7.1 you can only add Gallery Blocks to blog posts, product items, and individual events.

To add alt text to an image in a Gallery Block:

1. Double-click the Gallery Block or click Edit.
2. Find the image to edit, hover over it, and click .
3. Add alt text to the Image Title field. If you don't add an image title, text in the description field becomes alt text.
4. Click Save.

Video Block thumbnail image

When you add Video Blocks to your page using a URL, the block automatically generates a thumbnail image and appears as an overlay. If you add a custom thumbnail, the file name appears in the static URL, but not as alt text. It's not possible to add alt text to Video Block thumbnail images. 

Product images

To add alt text to a product image on the Store Page:

1. Hover over the product and click Edit.
2. Find the image to edit, hover over it, and click .
3. Add alt text to the Image Title field. If you don't add an image title, the product title becomes alt text.
4. Click Save.

Cover Page images

Cover Pages are only supported in version 7.0.

To add alt text to a Cover Page image:

1. In the Cover Page menu, click the Media panel.
2. Hover over the image and click .
3. Add alt text to the Enter alt text… field.
4. Click Save.

Site logo

The site title serves as the alt text for the site logo. 

Blog post and event thumbnails

The title of a blog post or event serves as the alt text for the post or event thumbnail. For Event Pages, this is the same on both list and calendar layouts.

Page thumbnail image

File names serve as alt text for page thumbnail images. Ensure that you name all thumbnail images as you want them to appear before uploading them.

Image file names

An image's name acts as alt text if there isn't any other alt text provided.

To change the filename for most images, re-upload the image with the new name. For Image Blocks, open the image editor and update the Filename field in the Content tab.

Tip: Only use letters, numbers, underscores, and hyphens in file names.

Next steps

• For more tips on SEO, visit How do I increase my site visibility to search engines?
• For more tips on making your site accessible to people with disabilities, visit Making your Squarespace site more accessible.