iMovie Theater Thumbnails/Posters

I have tried many of these solutions to set a Poster frame in a video with Imovie, but at the end nothing works.

For example, if you make a video in Imovie and you want to sent in your youtube channel, there is no way to set the poster frame you need.. I have check many differents configurations with last softwares updates included but nothing works like it's supposeed to do in Imovie for this (choice before export)..

Extremely helpful. One detail to add is that you need to Share to a File to see the image you can move the mouse over to choose your thumbnail.

I found that need to keep the Thumbnails folder of the iMovie Theater package open, and while the Share and Upload to iCloud process is running, a thumbnail file appears in this folder and then disappears when the upload is complete. To intercept the thumbnail creation during the iMovie Theater upload, follow these steps:

1. Open the Thumbnails folder in the iMovie Theater package that is in the Movies folder.

2. Start the iMovie Share to Theater and make a copy of the thumbnail file with the really long name that will appear.

3. Open the copied file in an image editor and copy a screenshot of the thumbnail you want over top of the one iMovie randomly selected. Save the image as a .PNG with a name like "replace.png".

4. Make a small change to your movie so iMovie will replace what is in the Theater when you will perform a second upload in step 5.

5. Share the movie to Theater again, and when you see the iMovie-generated thumbnail file appear in the Thumbnails folder, quickly copy the long name, delete that file and rename "replace.png" to the long name.

6. After the upload is complete, close iMovie, re-open it and you should see your thumbnail.

Thank you for this excellent answer Cameron!! Ridiculous that you need to use this kind of workaround but it DOES work exactly as required.

Does not work in current version of iMovies.

Thanks. This worked for me in version 10.1.4.