scale smalllogo and biglogo

If the the images used as smalllogo and biglogo have different length-to-height rations than the example images, they do not fit in that well. In my case, the logo is a bit too high. It results in a too large logo on the title slide and a too small logo on content slides.

I could not find any option to scale the logos. Do you have any suggestions how this can be achieved easily? Or would it be an interesting additional feature, eventually?

Thank you in advance!