How to add image alt text to images

Alt text helps people who may not be able to see an image for various reasons by providing a textual description which accompanies the image. A significant guide to alt text, why it is important, and how to achieve good alt text is here:

On the desktop web client, when writing a post, you can add an image by clicking on the paperclip icon on the bottom menu on the left.

  1. Once your image is uploaded, click on ! No description added over your image.
  2. You will then see a popup allowing you to add a text description of your image. Try to be as clear as possible in your description. It’s okay if it’s short.
  3. Click Apply and that’s it! You can then publish your toot normally.
  1. Once the image is uploaded you can either tap edit or No description added
  2. Enter your description
  3. Tap Apply (you will note the No description added text disappears)
  1. Once an image is uploaded, tap Add image description
  2. Tap Save, then publish as normal.
  1. Once you have uploaded the image, press and hold it for a few seconds.
  2. Let go and choose Set Caption from the menu
  3. Once captioned, select OK and publish your toot.

Screenshot of the Mastodon web client showing Compose box options dialog. The "Show confirmation dialog before sending toots lacking media descriptions" option is checked and highlighted. On the web client (desktop/mobile):

  1. On the main page, click App Settings in the menu
  2. Under Compose box, enable Show confirmation dialog before sending toots lacking media descriptions

While this functionality is available in the web client (regardless of accessing via a mobile browser or desktop), it is unlikely to be present in your mobile App. As of writing it is not available in Tusky or the official Mastodon App for Android.

You can follow to remind you to add alt-text in case you forget.