On Windows:
Looks like this has been covered in the past but I can't determine if there is now capability: For certain, -print <file> and /print <file> don't perform

To print a file from command line (via batch file or launched from another prog), to default or nominated printer. Full page, maybe just using the printer default settings. No fuss, no gui - maybe a bit of run time "Hey, I'm good/in trouble" info and an exit code.
I'm trying to have an image auto-print when its file arrives in a nominated folder (from a scanner), then get deleted etc. ~Trying to rig up a photocopy utility for a non-multi-func printer using a networked Brother scanner that can output direct to a remote folder, without having to leave the scanner.
Also would like to run this on Windows home Server but I don't think this is so much of an issue.
Any suggestions re watching a folder and launching a print job also welcome.
Very many thanks to all involved with Xnview - fantastic bit of kit!!
Pete