Here are ways to remove media from drop zones:
From the menu, drag the image, slideshow, or movie out of the drop zone.
When your pointer is outside the drop zone, the media is deleted in an animated puff of smoke.
Open the drop zone editor by clicking the drop zone button (shown below), by choosing Project > Edit Drop Zones, or by double-clicking a drop zone.
Drag the media out of the drop zone, or select the drop zone and press Delete.
To remove individual images from a slideshow in a drop zone, open the drop zone editor. Double-click the drop zone that holds the slideshow, which opens the slideshow editor. Delete the unwanted images, and then click the Return button to go back to the drop zone editor.