Click the Effects button.

Browse through the effects and the stock backdrops with silhouettes.

With some distortion effects, a slider appears when you move your pointer over the image. Move the slider to see how the distortion changes the photo or video.

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Click the Effects button.

Browse through the effects until you reach User Backdrops.

Drag a photo or video to one of the User Backdrop frames. You can drag a photo or video from your desktop, the Finder, iMovie, or Safari.