Another note: Windows will only allow one thread, so you cannot create childs, (which is what I THINK you mean by in parralell. What I am currently doing is akin to this:

@dir(Standard, large, xl
 for loop of @dir
  process_img();
 }

sub process_img
Create thumbnail and save in appropriate sub folder;
Create medium size and save in appropriate sub folder;
Rotate image 90 and save in appropriate sub folder;
}
[download]

So as well as original, I end up with graphics in thumb, medium and upright folders within each of the three folders above