Yes the templates do have it set to center; however with a large shadow image to the bottom the inset product image wants to be slightly higher, otherwise for a thin image you get a larger black bar at the top than the bottom.
Look at the Siemens thumbnail on this page:
http://www.totalformat.com/reviews/s...p?cat=11&page=
The thumbnail is set too low, hence the imbalanced black bars top and bottom.
If you do what you ahve suggested to the $catimage statement it won't work.
If one product has no thumbnail, it picks up the previous product's definition (because $catimage is still definined from before and it's not be reset) and will display the previous thumbnail again.