Company logo

Hey at all
we are currently facing a problem, for that we need a solution. The images uploaded by our users as the “company logo” are sometimes not in a squared layout, they are rectangular.
If this is the case, the thumbnail in somekind of way zooms into the center of the image, so that only a little piece of that is shown. Is there a way to get the rectangular images fit? Like getting a white space aournd the image or something?