Use this command if you want to trim your imported images by marking the four corners of each image. This is particularly useful for trimming frames from a strip of negatives or from a scanned print. To use this command, you must have overscanned the negatives or prints so that the edges of the frames are visible.
Use this command if you want to trim your imported images with a fixed size rectangle. This is useful when you don’t need to square up your imported images or when the corners of the frames are not visible. You use the Trimming properties dialog box to set the width and height of the trimmed images.