Make product images (both landscape and portrait) square without cropping

To make a store with the category images look consistent, my wish is to display product images both landscape and portrait as original as square images without cropping. So the product title under the product image are aligned.

Is there a way to let the height (in case of landscape original) or height (in case of a portrait original) be filled out with e.g. a white color? Now I edit all my images before uploading, but if there is a way to automate this while uploading, it would save me a lot of time.