How to add alt text to a signature image in Outlook

Alt text is the description a screen reader announces in place of an image. In classic Outlook for Windows, set it in the signature editor: go to File > Options > Mail > Signatures, right-click the image, choose Picture, then fill in the Alt Text tab. Alt text typed in a message body only applies to that one email.

How do I add alt text to a signature image in Outlook?

1. Select File > Options > Mail.
2. Under Compose messages, select Signatures.
3. Select the signature you want to edit, or create a new one.
4. Right-click the image and select Picture.
5. Select the Alt Text tab, type a description, and select OK.
6. Close the signature window with OK.

These steps come from Microsoft's accessibility video, under the heading "Create an accessible signature".

Why is there no alt text option in the right-click menu?

In a message body, right-clicking an image gives you an alt text option. Microsoft calls it View Alt Text in some versions and Edit Alt Text in others. In a 2020 Microsoft Q&A thread, a user reported that the same option is missing when editing a signature. A reply said to use Picture and then the Alt Text tab, and that worked for the user. Use that path.

What should the alt text say?

Microsoft asks for one or two sentences that describe the object and its context to someone who cannot see it. For a logo, the useful information is whose email this is, so write the company name. If the logo contains words, repeat those words in the alt text. The W3C images guide puts the general rule this way: images need text alternatives that describe the information or function they represent.

When should a signature image be decorative?

A decorative image needs no description. Microsoft's alt text page gives stylistic borders as an example, but it documents the Mark as decorative option for Word, Excel and PowerPoint, not Outlook. The W3C guide says to use an empty alt attribute (alt="") when an image only decorates the page. An icon that repeats the text beside it, such as a phone symbol next to a phone number, usually adds nothing for a screen reader user, so treat it as decorative. I could not confirm the checkbox in the signature editor. If it is not there, write a short description instead.

Why does the alt text disappear?

• You typed it in the message body. That change belongs to one message. Open the signature editor and set it there.
• You did not save the signature. Close the signature window with OK, reopen it, and check the alt text is still there.
• You are not checking the sent result. Microsoft says the Accessibility Checker runs in the background while you compose, and recommends it for finding missing alternative text. Compose a message with the signature in it and read what the checker reports.

How Sendoff handles this

Every image Sendoff generates has an alt attribute, so you do not have to add them one by one:

• Logo: the company name from your company field. If that field is empty, the alt text is "Logo".
• Photo: the person's name, or "Photo" when the name is empty.
• Social icons: the network name, such as LinkedIn.
• Small contact icons: an empty alt attribute, so screen readers skip them.
• Banner: the "Banner alt text" field in the editor.

Fill in the company name before you copy the signature. The signature checker reports any pasted image that has no alt attribute. For setup steps, read the Outlook integration page. If your images are missing in general, not only their alt text, read why Outlook signature images do not show. You can build one in the free generator.

What this guide does not cover

I could read official Microsoft steps for classic Outlook on Windows. For new Outlook, Outlook for Mac and Outlook on the web, I found no official Microsoft page that covers alt text in the signature editor, so check the menu in your version before following step 4.

Sources

• Microsoft Support, video "Improve email accessibility" (section "Create an accessible signature"): https://support.microsoft.com/en-us/outlook/accessibility/video-improve-email-accessibility
• Microsoft Support, "Add alternative text to a shape, picture, chart, SmartArt graphic, or other object": https://support.microsoft.com/en-us/office/add-alternative-text-to-a-shape-picture-chart-smartart-graphic-or-other-object-44989b2a-903c-4d9a-b742-6a75b451c669
• Microsoft Support, "Outlook: Missing alternative text": https://support.microsoft.com/en-us/office/outlook-missing-alternative-text-920333c1-47f7-4db0-be54-a4e6358b464c
• W3C Web Accessibility Initiative, "Images Tutorial": https://www.w3.org/WAI/tutorials/images/
• Microsoft Q&A, "How to add 'alt text' to image in signature" (February 2020): https://learn.microsoft.com/en-us/answers/questions/4563933/how-to-add-alt-text-to-image-in-signature