Where does the visitor image on Zendesk Chat come from?
On Chat, the visitor image that appears depends on how the visitor starts the chat. If a visitor can start a chat without signing in, the visitor image is blank with a random-colored background.
When the pre-chat form is enabled the visitor image that appears depends on how the visitor signs in. When the visitor signs in with their email address, the visitor image is pulled from their Gravatar profile if their email address matches. If the visitor signs in from a social profile (Facebook, Twitter, Google), the visitor image is pulled from the image on their social profile.