This will select everything on your timeline. Click anywhere in the timeline, then press and hold your Command key and hit “A” on your keyboard.Select the images on your timeline in one of the following ways.Save some elbow grease by selecting the images first and applying a uniform duration to all of them with a few simple clicks. It sounds simple, but the process can be tedious if you plan on adjusting each image individually. So, you need to create a slideshow where each image is displayed for the same length of time. Change the Duration of All Photos in Your Current Project on a Mac
Fortunately, there are several ways to cut down on the labor needed using the Mac app for iMovie. This can mean hours of monotonous clicking when you have hundreds of images inside your project.
You can adjust the duration of an item on your iMovie timeline by grabbing its edge and dragging it left or right. Change the Duration of All Photos in iMovie on a Mac iPhone and iPad users may also want to stick around for a few helpful tips. Work smart instead of hard and adjust all images at once by following the steps below on your Mac device. If you’re working on a slideshow or a similar project in iMovie, changing the duration of each image can be time-consuming.