are you running 1.3.5? i had applied those 'patches' to a new 1.3.5 install and it had no effective result. i was also getting js errors, but due to something with the 'hot zone'; disabled 'hot zone' and no js erros.

at http://breakmyzencart.com/ih-doc the bottom example says

"You specified 100×80 for your small images and 150×120 for your medium sized images. "

but the admin panel gives no option for medium size - it only gives you a choice for small image size under configuration>>images. IH2 only gives you the choice to upload a file for medium size, not to actually set the size within the panel.

got any pointers for this?