How to Call in Different Logos For themes

Hi,

I have a multi site WP install network set up, and I managed to get the logo changed for the 2nd WP site in this network. However, I can not manage to get the logo changed for the main site due to the file is called: logo.png and it is already uploaded for the 2nd site?

So, can someone here kindly tell me is it possible to have different logos for different WP websites that are inside of the multi- site network set up?

If so, please please can someone tell me how I can get this sorted or what files and codes I would need to add in to make each website pull in their own unique logo.

thanks and I will be awaiting some help soon if this is doable or if it is not either way I need to know before continuing to build out this network.

thanks everyone

Libby