We usually see a sender's photo in Gmail. Those sender avatars are shown not only for our friends and known contacts, but also for transactional emails.
I often wondered how they are shown. They look good and provide a better clue about the sender.
Turns out there is a "BIMI" (Brand Indicators for Message Identification) spec for that. It requires DMARC compliance and then a DNS record pointing to the SVG image.