All command line options are case sensitive, file names are not:
"File Name 1" "File Name 2"
opens the specified file(s).
Note: if no full path is specified the file(s) must reside in the same directory as the program (not the current directory).
"New File Name"
if the given file is not existing the program creates an image from the clipboard and opens it.
Note: if no full path is specified the file will be created in the same directory as the program (not the current directory).
will start a recursive slideshow from the given folder.
/p "Image Name"
opens the image in print preview mode.
"Image Name 1" "Image Name 2" /pt "Printer Name" "Driver Name" "Port Name"
prints the given image(s) to the optionally specified printer. If no printer name is specified the program's default printer is used.