How to Add Alt Text to Images on Threads for Accessibility

Adding alt text to images on Threads makes your posts accessible to people who use screen readers or have visual impairments. When you upload a photo without a description, screen readers cannot convey what the image shows. This article explains how to add alt text to every image you share on Threads, covering both mobile and web workflows.

What Alt Text Does and Why It Matters

Alt text is a written description embedded in an image’s metadata. Screen readers read this description aloud so users who cannot see the image understand its content. On Threads, every image you upload must have alt text to be fully accessible. The feature is built into the post composer and requires no extra tools.

Threads supports alt text for single images, carousels, and images shared in replies. You can add alt text to each image separately within a multi-image post. The platform does not auto-generate descriptions, so you must write them manually.

How to Add Alt Text on the Threads Mobile App

The mobile app for iOS and Android offers the same alt-text workflow. Follow these steps for each image you want to describe.

1. Start a new post
   Tap the plus icon or the compose button at the bottom of the screen to create a new Thread.
2. Attach an image
   Tap the photo icon to select an image from your gallery or take a new photo with your camera.
3. Tap the Alt icon
   On the image preview, look for the Alt button in the bottom-right corner. It appears as a small badge with the letters “ALT” inside.
4. Write your description
   A text field opens. Type a clear description of the image. Include important details such as people, objects, text, colors, and actions. Keep it concise but complete.
5. Tap Done or Save
   Close the alt text editor. The Alt badge now appears filled or highlighted to confirm alt text is added. Repeat for each image in a carousel.
6. Post your Thread
   Tap Post to share the accessible image with your audience.

How to Add Alt Text on Threads Web

The web version of Threads at threads.net uses a similar process. The interface is slightly different but equally straightforward.

1. Open the composer
   Click the New Thread button at the top of the feed or click the text box that says “Start a thread.”
2. Upload an image
   Click the image icon in the composer toolbar and select a file from your computer.
3. Find the Alt text button
   Hover over the uploaded image. A small Alt button appears at the bottom-right corner of the image thumbnail.
4. Click Alt and type a description
   A pop-up window opens where you can enter the alt text. Write a descriptive sentence or two.
5. Save and post
   Click Save to close the pop-up. The Alt badge turns blue or bold to indicate alt text is present. Click Post to publish.

How to Edit Alt Text After Posting

You can change the alt text on a published Thread. This is useful if you notice a typo or realize the description is incomplete.

1. Open the post
   Tap or click the Thread you want to edit.
2. Tap the three-dot menu
   Look for the three horizontal dots in the top-right corner of the post.
3. Select Edit
   From the menu, choose Edit. The post composer opens with your existing text and images.
4. Tap the Alt badge on the image
   Tap the Alt button on the image to open the alt text editor. Update the description as needed.
5. Save changes
   Tap the checkmark or Save button. Then tap Done to finish editing the post.

Common Mistakes and Limitations

Alt Text Is Blank After Posting

If you skip the Alt button, the image will have no alt text. Screen readers will read the filename or nothing at all. Always verify the Alt badge is active before posting.

Alt Text on Carousel Posts

Each image in a carousel requires its own alt text. You must tap the Alt icon on every image individually. The app does not copy alt text from one image to another.

Alt Text in Replies and Quote Posts

When you reply with an image, the same alt text rules apply. Open the reply composer, attach the image, and add alt text before sending. Quote posts that include an image also need alt text on that image.

No Automatic Alt Text Generation

Threads does not generate alt text automatically. You must write descriptions yourself. This is a deliberate design choice to ensure descriptions are accurate and context-aware.

Alt Text Best Practices Compared

Practice	Good Example	Bad Example
Be specific	“A black Labrador retriever sits on a green lawn holding a red ball”	“Dog with ball”
Include text	“A sign reads ‘Open 24 Hours’ in white letters on a blue background”	“Sign”
Describe actions	“A woman in a yellow jacket pours coffee into a white mug”	“Coffee being poured”
Avoid redundancy	“Screenshot of a tweet: ‘Hello world’ in black text on a white background”	“Image of a tweet screenshot”

Now you can add alt text to every image on Threads using the mobile app or the web interface. Start by writing clear, specific descriptions for each photo you share. For posts with multiple images, remember to add alt text to every one individually. After posting, use the Edit option to correct any mistakes in the alt text.