Hello pinguas!
You can add your logo to the header and the footer of the Fusion theme. You have to edit the code in the following files.
theme/fusion/layout/frontpage.php
theme/fusion/layout/general.php
You can add the image code to the Header and Footer sections that are labeled the following:
<!-- START OF CONTENT -->
<!-- START OF FOOTER -->
The Logo will need to be uploaded to your server or you can hotlink to your logo in the code. Please read the following article for more information if you get stuck on how to do this. Hope this helps.
Adding a logo through the theme code in Moodle
Best Regards,
James R