Can I add a logo to an alert?

Summary:

I've seen several discussions about changing the Sender email address on Alerts. It seems that is not possible if the latest posting is right. So to make things look more official, is it possible to add a logo to the Alerts? Also, someone mentioned the Alias name could be modified. Is that actually possible?

Content (required):

In this time when we have to educate our people not to click on links from outside the company, we keep sending links from outside the company from our Oracle system. I've done several things to make it look official, but a logo, an alias and actually fixing the sender email would go far to make this clear. I've already got the site whitelisted so at least the emails do not arrive with the yellow banner warning we put on other "out of the company" emails. The last posting I saw on this subject was a couple of years ago.