Add alt text to images in PDFs

Alt text describes an image for people who use screen readers or otherwise cannot perceive the image. Waterfox lets you add alt text manually when inserting an image into a PDF, or add it later to an image already in the document.

Add an image and write alt text

1. Open a PDF in Waterfox.
2. Click the image icon in the PDF viewer, then click Add image.
3. Choose an image. Waterfox opens the alt text editor.
4. Either:
   • Write a concise description that communicates the image’s purpose or important content.
   • Mark the image as decorative if it adds no information.
5. Click Save. Clicking Not now discards the text entered in the editor.
6. Waterfox confirms that the alt text was added.
7. Position and resize the image as needed.

If an image has no alt text, Waterfox may display Missing alt text on the image. This indicator is not included when the PDF is printed. Click it at any time to open the editor.

Alternative control layout

Some Waterfox versions use this layout:

1. Click the image icon at the top-right of the PDF viewer.
2. Click Add image and choose an image file.
3. Select the image, then click + Alt text.
4. Write a description or mark the image as decorative.
5. Click Save.
6. Drag the image to position it. Drag its borders to resize it.

Add or edit alt text later

1. Open the PDF in Waterfox.
2. Click the image icon in the PDF viewer.
3. Select the image you want to update.
4. Click Alt text or Missing alt text.
5. Edit the description or change the decorative setting.
6. Click Save.

Alt text editor settings

1. Open the overflow menu in the PDF viewer and select Image alt text settings.
2. Choose whether Waterfox should open the alt text editor immediately after you add an image.
3. If the editor does not open immediately, select the image and click its alt text button whenever you want to add a description.

Tips for writing alt text

Alt text should briefly communicate the image’s purpose and the information needed to understand the surrounding PDF content.

• Describe the important content or function, not every visual detail.
• Keep the description concise and use plain language.
• Avoid starting with “image of” or “picture of” unless the medium is relevant.
• Do not repeat nearby text that already provides the same information.
• Mark purely decorative images as decorative.

For more guidance, see:

• W3C image accessibility tutorials
• American Foundation for the Blind: Writing Effective Image Descriptions or “Alt Text”
• Harvard University: Write helpful alt text to describe images
• Washington Post alt text guidelines

Frequently asked questions

Can I skip adding alt text?

Yes. Click Not now to close the editor without saving. Waterfox may continue to show Missing alt text so you can return to the image later.

For an informative image, adding a useful description makes the PDF more accessible. For an image that adds no information, mark it as decorative instead of leaving its purpose unclear.

Will alt text appear when the PDF is printed?

No. Alt text is part of the digital document. A screen reader can read it, and compatible PDF viewers may expose it, but it is not printed on the page.

Should text inside an image be included?

Include text that is important to the image’s meaning and is not already available elsewhere in the PDF. Keep the description focused on what the reader needs from the image in context.

---