In your AdServer there are numerous possibilities to adapt it to your corporate identity. Under Settings -> Global settings -> ... you will find the various options for making an adjustment under the individual items.
To make uploading easier for you, you will find an upload button in front of the fields for the logo URL.
Settings -> Global settings -> Company data -> Adserver-webseite
Upload the logo in 196x86 format as a JPG file
Settings -> Global settings -> Reports -> General
Settings -> Global settings -> Reports -> Own reports
Upload the logo in 200x90 format as a JPG file
Settings -> Global settings -> Reports -> Campaign reports
Upload the logo in 820x180 format as a JPG file
Settings -> Global settings -> Text templates -> General
Upload the logo in 300x100 format as a JPG file