Cropping in Preview

Is is possible to crop 50% in Preview, or in Photoshop? Is is possible to use Automator to crop? The trick here is 50%. My goal is to open up the a scanned book page and cut it into pages. Thanks any ideas.
AB

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This seems like the perfect task for a PhotoShop automation batch. For example, I would create an output folder in the Finder, then open some image in PS and record (eg):
-Duplicate image
-Crop, save in target folder, close
-Crop original, save in target, close
-Stop recording

Then, menu File > Automate > Batch. Choose your action, source folder (the one containing all the images), and go!

In Photoshop 7, I can only seem to crop to an inch or pixel size. It feels like I’m missing something. There is a fine Preview Crop Automator workflow posted at Apple by kylepoint.com:
http://www.apple.com/downloads/macosx/automator/usefulimageworkflows.html
The trick here is cropping 50% to the left half, or 50% to right half versus cropping 25% from each side. Should I AppleScript, create an Automator workflow, or dig further into Photoshop?
-AB

Thanks Jacques - I don’t think I’ve used the Graphic Converter. What a perfect time to try.
I’m getting a “Expected end of line but found identifier” at

set The_dimensions to get file imageinfo x

I’m not sure where to trace that error to.

This compiles correctly. I’ll need to plug the info into tomorrow.
Thanks!
-AB

Just for the records, in PS you can also canvas-size to 50% (which is virtually the same than crop).