I don't have PhotoShow on this computer. If I remember that, in the dim, dark past, that the problem may be related to the size and resolution of the images. If you are still playing for PhotoShow, contact Roxio/Corel support.
PhotoShow should have been euthanized many years ago and subscriptions refunded after a suitable time for people to download their PhotoShows.
See if you can find a free version of Corel's FastFlick. It used to be readily available but now is part of other Corel Products. USe it with templates to make a video file and then use Power2Go (free) to burn it to disc.