Replacing images in pre-programmed show

I was able to do this about a year ago, so I know at one time it worked. I want to create a “dummy” show with about 250 images prior to going on a trip so that the timing and all the work is done. At the end of the trip I want to replace the “dummy” slides I used to create the “dummy” show with new slides taken on the trip. The “dummy” images are named 0001 - 0250. I will name the new images with the same numbering and then replace the old ones with the new ones in the source folder. I remember doing all of this via the Package Contents File folder for the show. After replacing the files Fotomagico would rebuild the show. Once rebuilt the show plays as it was created, only with the new images.

That was a year ago. Now when the show is saved, Fotomagico renames all of the original files, making it impossible to replace them with the new files. Does anyone know a way to accomplish what I am trying to do? Bottom line is that I want to create the show prior to the trip with dummy slides and replace those slides with new images without having to drag each image in one at a time and resize them one at a time. Replacing the original source folder with images numbered in the same manner seems like the best option, but I cannot get it to work any longer. Thanks.