Making use of thumbnail images

[fakeDecoy]

What template file would I edit to have the system use either images/medium or images/small for thumbnails for the product listing display?

For some reason I had my store set up with the main images directory holding the small images, and images/large holding the full size. I gather that this is nonstandard behavior, and I ran into trouble with a module, so I copied all large images to the main images directory. And now of course the thumbnails are all using the full size 800x600 images and resizing them, making for a long load time.

[mc12345678]

Image Handler (in your case version 3) would be suggested to address that. As to which image to load where, generally the medium image is loaded as the image on the product info page, with the large image available for viewing the large image and the small used on product listings, otherwise the "medium" image is used everywhere (when the only image loaded for the product).

As to file(s), there is a template file for the main_product_image I think it is includes/templates/YOUR_TEMPLATE/templates/tpl_modules_main_product_image.php with others for additional images, etc... there are other files involved with identifying the specific image to load. My suggestion there though is to look at the files that image handler modifies and basically those are the ones that may have been affected by something else and may need restoration.

[DrByte]

For some reason I had my store set up with the main images directory holding the small images, and images/large holding the full size. I gather that this is nonstandard behavior

No, actually, that's normal.