batch thumbnail / image processing

[amateurcanada]

I have 600 directories. Each has images in them, I wish to make thumbnails in 3-4 different sizes, and resize the images as well. Priority being the thumbnails to automate.

What would you guys recommend, or what do you use..

I currently use ACDSEE and ARLES.

[hzoltan]

Advanced Batch Converter

[u-Bob]

perl + imagemagick

[Subtle]

How about Xnview?