Hi there,

What program are you using? Version 14 or and older version of Movie Edit Pro? If so, you just need to place the still photo file into a parallel track of your video with a higher track number. This will make the photo appear in front of video, covering up the video. Now you can right-click on the photo object in your timeline and choose the "Image size and position" dialog from the context menu. This is where you can easily adjust the size and position of the photo object by using your mouse and the orange handles on the edges of the photo. In Video Pro X or Movie Edit Pro 15 you would access the size & position settings via the "Effects" tab in the media pool (under "Movement effects") instead of the context menu and the additional dialog.

I hope this helps.