Slipping a Reference Image
A reference image that is offset in time can be overlaid on the canvas. You can slip a front, matte, result, output matte, source front, and source matte clips. In the Sources list, use the Slip field to indicate the offset amount.
Each slip value can be set independently. To set the same front and matte values for a source, hold down the Alt key and edit either value.
(a) Front and Source Front Slip fields (b) Matte and Source Matte Slip fields