Icon image sizes

I’ve just added this to a client site to allow downloads of Word and Powerpoint documents. However, the icons for the two files types are different sizes which looks all wrong.

Any idea how to get them the same size?

Here is a screenshot:

https://www.dropbox.com/s/qs3kogxnbtwf2it/Download%20manager%20icon%20sizes.jpg?dl=0

https://www.ads-software.com/plugins/download-manager/