How can Automator or Applescript rotate 500,000 images in subfolders

Hi Everyone,
I have very specific question.
I’ve got 500,000 images that sit in 98 subfolders. Some of the subfolders contain 25,000 images.
Now my question: is there any script/automator workflow that I can use?
I was trying to create a workflow:

  1. Ask for Finder Items
  2. Get Folder Contents (tick repeat for each subfolder found)
  3. Rotate images
    It works OK, but only for these folders where there is less than 4,096 files:
    I normally receive following error message:
    ‘Rotate images failed - 1 error
    too many arguments (12019) – limit is 4096’
    Is there any way to increase this limit or create completely different apple script?
    I really hope that someone will help me with this one.
    By the way my OS is Mountain Lion
    Thank you

Assuming every file in the folders is an image file:

set mainFolder to POSIX path of (path to desktop as text) & "My Folder"
do shell script "find " & quoted form of mainFolder & " \\! -name \".*\" -type f -print0 | xargs -0 sips -r 90"