iMovie for iOS (iPad): Removing a video clip or photo from a project
When you remove a video clip or photo from a project that you added from the Video browser or Photo browser, it’s removed from the project but is still available if you want to use it again. If you delete a video clip that was recorded into the project or was embedded as part of an imported project, that video is permanently deleted unless you first move it to the Camera Roll. If you remove a photo that you took with your device into a specific project, the photo is permanently deleted from your device and can’t be retrieved.
Delete a video clip or photo from a project
With your project open, in the project timeline, tap and hold the video clip or photo until it pops off the timeline.
Drag the clip or photo out of the timeline until you see the puff of smoke in the corner of the clip, then release.
You can also double-tap the video clip or photo, then tap Delete Clip in the Clip Settings or Photo Settings window that appears.