The Amiga has a powerful multitasking operating system that allows several different programs to run simultaneously. ARexx is a system that allows these programs, even if written by different programmers and different publishers to all communicate and control each other via a common language. This lanugage, called ARexx, is included with your Workbench 3.x and is almost certainly already installed on your computer.
ARexx is powerful enough to take complete control over your programs, so you can sit back and watch as the ARexx program (usually called an 'ARexx script') happily processes hundreds of images for you - ARexx is just perfect for long tedious repetetive tasks such as converting hundreds of images from one format to another, or building animations.
How to program ARexx is beyond the scope of this manual, but there are plenty of books available for budding ARexx programmers to read (many, but not all, Amiga systems come with the official ARexx manual as standard - although you may find the commercially available books a much better read!)
For those wanting to jump in at the deep end and start ARexx programming, why not look at the example scripts supplied with Photogenics? The shorter ones should all be pretty self explanatory, and are pretty easy to hack-around with and change. Experimentation with ARexx this way is a great way to learn the language!
To run Rexx scripts, Photogenics obviously requires ARexx to be installed on your system (with an official Commdore install, the RexxMast program lives in the System drawer on yur Workbench, and the command calling stubs ('rx', 'rxc', 'tco' &tc) live in the directory 'sys:Rexxc' - Photogenics is set up to expect this system). Make sure RexxMast is running before trying any scripts - the best way to do this is put RexxMast in your WBStartup drawer if RexxMast isn't started by another package already.
It seems that ARexx can't handle scripts placed in directories with spaces in the pathname (in devices OR directories) - this means that if you've installed Photogenics in a drawer with a space in the name (eg 'Art Packages') or if your volume name has a space (eg 'Work Drive:') then the ARexx Macro menu won't be able to launch anything.
It's not a Photogenics problem, it seems to be a limitation in the ARexx 1.15 release as supplied with the v2.x+ OS, as simple console I/O scripts exhibit the same problem if you make a subdirectory in your rexx: drawer and put a space in the name, then put a known-to-work script in it, and launch with 'rx "rexx:a b/script.rx"' - it fails when it shouldn't.
If you get problems, move the contents of your Photogenics:data/Scripts directory into your 'REXX:' directory.
Photogenics will check for a script 'Photogenics:data/scripts/PgsStartup.rx' when it starts up - it it's found, it will automatically be run. This makes it easy for other scripts and programs to launch Photogenics and then make it run a script instantly.