Apparently there isnt one.
I paid for a theme from one of the "premium" developers and found it was built around this script, when I asked how I could remove it I was told I could't (I wasnt happy with the badly cropped thumbnails it created).
I found a hack that modified the script so it would crop from 'top center' rather than 'center center' and although this was far from perfect it was acceptible.
However the site I bought this theme for is intended to be heavily promoted and I found out 2 days ago that ALL of the thumbnails on my site (which are generated by this script) cant appear on other websites because its coded into this script.
So it looks like I have to delete a few weeks work and the money I paid to start over.
Avoid this script at all costs