Adding files to PhotoStage can be done using the command line. The PhotoStage executable is usually located at "C:\Program Files\NCH Software\PhotoStage\photostage.exe". The usage of command line is:
Usage: photostage.exe [file(s) to add]
where:
File(s) to Add contains a list of files to be added to PhotoStage. Each entry should be an absolute path separated by a space. Files will be automatically added to the sequence.