If you use a different picture for the overlay, do you get the same problem? What is the format of that file? When you open the project, do you get a message saying there is a missing file?
In attempt to fix this issue, please try the steps below:
Uninstall PhotoStage, then delete 3 folders named "PhotoStage" and 1 named "Components" from these locations:
**C:\Users\<username>\AppData\Roaming\NCH Software\PhotoStage\
**C:\Program Files (x86)\NCH Software\PhotoStage\
**C:\Program Files (x86)\NCH Software\Components
**C:\ProgramData\NCH Software\PhotoStage\
**If you can't find any of the folders, just continue.
After that, restart your computer and reinstall the program using this link: https://www.nchsoftware.com/slideshow/pstagesetup.exe
Once done, restart your system one more time and try again.