With VideoFactory, probably the best thing to do is to create a still image of the frame in a .jpg file. Position the cursor on the timeline to show the frame you want. Right-mouse-button click on the preview window and choose "display at project size", then click on the little floppy disk icon above the right corner of the preview. This will let you save the frame as a JPEG file. Place this newly created still image on the timeline and stretch it out as long as you want.