Half good news: I've got it all working properly but I had to edit "additional_images.php" and "main_product_image.php". I removed "/large" and "/medium" from "main_product_image.php" and also removed "/large" from "additional_images.php" so now all pictures are read from the main directory, i.e., "images/toshiba/xxxx.jpg". The good thing is, IH is basically doing it's job! All sizes are actually generated by IH, so even though I wasn't suppose to edit files to work it out, its an okay solution! :)