Trim a clip under 1 sec via Info

When you type 0.5 in the Info duration box, you should get a half second duration for the photo.

If you need it faster than that, put the photo into a Photos app slide show and export it as a video file. The import the video file into iMovie and use the speed adjustment controls to speed it up to as short as 0.1 second.

-- Rich

Go to iMovie/Preferences and set the duration there. I tried it at 0.5 seconds and when I created a new project and dragged in a photo the duration was 0.5 seconds. I didn't try it at a lesser duration.

However, as I mentioned in my previous post, you should be able to set the duration at least at 0.5 seconds, and maybe less, with the duration box in the iMovie project. Since that is not happening, you might try deleting/resetting preferences and see if that cures it.

To delete/reset preferences open iMovie while holding down the Option and Command keys and select to delete preferences in the box that appears. iMovie will open in a new library. Reopen your old library to get back to your projects.  Deleting preferences is a safe procedure that will not cause data loss or disruption to your project.

-- Rich

I don't know why you cannot get a duration less than 1 second. If you haven't already done so, try deleting preferences by opening iMovie while holding down the Option and Command keys and selecting to delete preferences in the box that appears. iMovie will open in a new library. Reopen your old library to get back to your projects.  Deleting preferences is a safe procedure that will not cause data loss or disruption to your project.

However, as a workaround, do your animated project with 1 second durations. Then export to your desktop and re-import the video back into a newly created iMovie project. Then you can use the speed adjustment tool to play the video faster and thus cut down the display exposure time for each image in the video. You can reduce the display time for the photos to 0.1 seconds if you want. Then export the new project.

-- Rich