Ro...
If I may offer my "wishlist..."

* Selection based (to isolate what area got pixelated). Default = all.
* A variable that would control amount (or ~ %) of pixelation, e.g., 1 = a few random squares, 10 = lots of squares
* Ability to choose size of square
* Squares isolated on a separate layer to which layer effects could be applied.
The first and third could be based on selections (converted to named alpha channels) made via an action that goes on to call the script.
The second could come from a reply to a dialog generated by the script.
What I'd give to know JS better! In the mean time, you
ROCK!
~Danny~