PowerPoint Image Alt Text: How to Generate With AI for Accessibility

Screen readers cannot describe images in a PowerPoint presentation without alt text. Writing meaningful alt text for dozens of slides is time-consuming and often skipped. Microsoft 365 includes an AI-powered feature that generates alt text automatically for most images, charts, and SmartArt graphics. This article explains how to use the AI alt text generator in PowerPoint, what its limitations are, and how to edit the results to meet accessibility standards.

How PowerPoint AI Generates Alt Text for Images

PowerPoint uses the Microsoft Cognitive Services computer vision API to analyze image content. The AI identifies objects, people, text, colors, and the general scene. It then generates a sentence describing what it sees. This feature is available only in Microsoft 365 subscriptions, not in perpetual versions like Office 2019 or 2021. The AI works for raster images such as JPG and PNG files. It does not generate alt text for vector graphics, embedded videos, or linked images from online sources.

The generated alt text appears in the Alt Text pane after you trigger the command. The AI description is written in English regardless of the presentation language. If the image contains readable text, the AI extracts that text and includes it in the description. Charts and diagrams receive a summary of the data trends rather than a full data table.

Prerequisites for AI Alt Text

You need a Microsoft 365 subscription (Business, Enterprise, or Personal). The feature is enabled by default. No internet connection is required for the initial detection, but the AI processing requires an online connection to Microsoft servers. If you are offline, the “Generate alt text for me” option is grayed out. You also need at least one image inserted into a slide. The AI cannot process empty placeholders or shapes without an image fill.

Steps to Generate Alt Text With AI in PowerPoint

Follow these steps to add AI-generated alt text to an image in PowerPoint for Windows or Mac.

1. Select the image
   Click the image, chart, or SmartArt object on your slide. The Picture Format or Graphics Format tab appears on the ribbon.
2. Open the Alt Text pane
   Right-click the selected image and choose Edit Alt Text. Alternatively, go to the Picture Format tab and click Alt Text in the Accessibility group.
3. Generate alt text automatically
   In the Alt Text pane, click the button labeled Generate alt text for me. PowerPoint sends the image to Microsoft servers and returns a description. This process takes one to three seconds per image.
4. Review the generated description
   Read the text in the text box. The AI writes something like “A man in a blue shirt sitting at a desk with a laptop and a coffee cup.” Check that the description matches the image content and context.
5. Edit the alt text
   Click inside the text box and edit the description. Remove irrelevant details. Add information the AI missed, such as the name of a person or the specific data point shown in a chart. Keep the final alt text under 150 characters when possible.
6. Mark the image as decorative if needed
   If the image is purely decorative and adds no information, check the box Mark as decorative. Screen readers skip decorative images entirely. Do not check this box for informative images.

Generate Alt Text for Multiple Images at Once

PowerPoint does not have a batch generation button. You must generate alt text for each image individually. To speed up the process, select the first image, open the Alt Text pane, generate the text, and then click the next image without closing the pane. The pane stays open and updates for each selected image.

Common Issues With AI Alt Text and How to Fix Them

AI alt text is completely wrong or describes the wrong object

The AI sometimes misidentifies objects, especially with abstract graphics, screenshots with complex layouts, or low-resolution images. Delete the generated text entirely and write a manual description. Use the format: “[Type of image] showing [key subject] in [context].” For example: “Screenshot of the Excel dashboard showing quarterly sales by region.”

Alt Text pane shows “No alt text generated”

This occurs when the image is a vector format such as SVG, EMF, or WMF. PowerPoint AI does not process these formats. Convert the vector image to a PNG or JPG by copying it into Paint or another image editor and saving as PNG. Then reinsert the raster version and generate alt text.

AI alt text is too generic or vague

The AI often writes generic descriptions such as “A group of people in a room.” This does not help someone using a screen reader understand the purpose of the image. Edit the alt text to include the specific context of the slide. If the image shows your team at a conference, write: “Photo of the marketing team at the 2024 Global Tech Summit standing in front of the company booth.”

The “Generate alt text for me” button is grayed out

This happens when PowerPoint is offline or when the image is linked from a website rather than embedded. Embed the image by inserting it directly from your hard drive. Check your internet connection and restart PowerPoint if the button remains disabled.

Manual Alt Text vs AI Alt Text: Accessibility Comparison

Item	Manual Alt Text	AI-Generated Alt Text
Accuracy	High when written by an author who knows the image context	Varies; often misses context and specific details
Speed	Slow for many images	Fast; one click per image
Decorative flagging	Author must manually mark decorative images	AI does not detect decorative intent; you must check the box
Text extraction	Author types any visible text manually	AI extracts visible text from the image automatically
Chart descriptions	Author summarizes the key data trend	AI provides a high-level trend but often omits exact numbers

The AI alt text feature saves time but never replaces human review. Screen reader users depend on accurate, concise descriptions to understand slide content. Always treat AI alt text as a first draft that needs editing. For presentations that must meet WCAG 2.1 AA standards, manual review of every alt text field is required.

You can now generate alt text for images in seconds using PowerPoint AI. Use the Alt Text pane to review and edit every description. For decorative images, check the Mark as decorative box. To further improve accessibility, run the built-in Accessibility Checker from Review > Check Accessibility after you finish editing alt text. This checker flags missing alt text and other issues such as insufficient color contrast.