You can upload custom Operator avatars in the SightMax Admin Console > click on an Operator name > upload a new image.
If you don't want to use Operator avatars and you want to use your own custom logo for all the Operators, please follow these instructions:
Edit the file on your server in AgentInterface\Scripts\chatframe5.js. Search for:
sQuery("#smOperatorImg").prop("src", "../sightmaxagentinterface/operator.smgif?accountId=" + this.AccountId + "&operatorId=" + this.OperatorId);
and replace it with the path to your own image, located on your server.
where "custom-operator-logo.png" is an image located in c:\inetpub\wwwroot\SightMax\AgentInterface - a file uploaded by you (company logo).
The image name can be anything you want.