Twist on reversing sequencial number

I'm not sure whether this can be automated easily, but I want to take a set of numbered JPGs and create a mirror copy of them in the same directory whose names reverse the sequence of the original files starting with their highest number.

Example:
Start with 10 files, img_001.jpg to img_010.jpg
Create 10 new files in the same directory named img_011.jpg to img_020.jpg, whose actual file contents are the reverse sequence of the original set.

If it makes it clearer, I want to create a single video from a mirrored sequence of images that appears to go through once in forward direction and then at the halfway point of the movie, reverses direction so that it ends up back at the first image. That way, when played in a video player on auto-repeat, the sequence appears to just flow smoothly in and out and back again in a perfect loop.

I can make it work through the interface but I don't know how to create a command line script that automates the determination of the file number at which to start the new set of files. I have to type the "new number" manually into my "renumber" rename batch. Is there a command line option to automatically determine the "new number" based on the last original file (plus 1)?

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Reply to #1:
Try this in a script method:

http://pastebin.com/Fd9dCpRP

put AR in "copy" mode, instead of rename.

put the output folder to "." only (a single dot, means current directory in windows, seems to work fine in AR)

Shouldn't have too many bugs..

numbering is fixed with 3 zeros, but it could be changed quite easily

cheers

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