Threads

Why did my multi-image Threads post fail? ("Threads only supports a single image or a video")

The Threads API accepts 1 image or video per post. Carousel posts are not supported via the API, even though the Threads app allows them when posting manually. A Threads post with multiple images fails with an error about the number of attachments.

To share multiple images, publish a thread instead: attach one image to each post in the thread (post 1 contains image 1, post 2 contains image 2, and so on). Follow the steps below.

Post a Thread with Photos

1. Open the Remix screen

2. Click + Add Post and select Threads

3. Write your first post and attach photos via "Add Media"

4. Click "+ Add to Thread" to add more posts to the thread

5. Attach photos to each thread post as needed

6. Schedule or publish

For an automated thread workflow, see: Email to Long Form Thread

For API thread posting, see: Twitter Threads (the same additionalPosts field works for Threads)