how do I change the image icon for my imovie on my mac book

Hi,

iMovie picks a random image from the middle of the movie to display as the thumbnail. The only way that I know of to change that is to add a black background of suitable duration to the beginning or end of the movie to change the midpoint. The frame then selected still may not be the one that you want.

To change the thumbnail display in the project media browser you an insert a still image of the thumbnail you want, into the upper time at about the midpoint of the movie. You would need to remember to delete the image from the upper timeline before sharing (exporting) the project.

For a shared movie that you intend to keep on your Mac, your can change the thumbnail display as follows: Share the movie to your desktop. Do a control-click/Get Indo on the movie's icon. That will reveal an information box. Leave it on your screen. Then put a still image from your movie onto your desktop. Open it. Do an Edit/Copy of the open image (the image, not its icon). Then select the little folder icon at the top of the Get Info box and do an Edit/Paste of the image into the folder icon..

The thumbnail will not carry over to other apps, however. It is just file data on your Mac.

-- Rich