This recipe should be very interesting for you if you have nice subcategory images of one size and manufacturer logos of a different size. Your index.php file that uses the middle block of the file for showing subcategory or manufacturer product listings only uses one set of sizing, which is HEADING_IMAGE_WIDTH and HEADING_IMAGE_HEIGHT. You will be able to define manufacturer image size independent of category image size.
The default size of 57 for HEADING_IMAGE_WIDTH and 40 for HEADING_IMAGE_HEIGHT looks fine for the subcategory images, as you can see in the following screenshot:
However, it often makes the logos too small and turns them into hard-to-read blobs, as in this screenshot:
The solution is to offer different sizing for logos and subcategory images so that the logo will not be squished, but will show the way it should.
Choose the pan that best fits your loaf, and get baking!