Speak allows you to customize your Ai Meeting Assistant name and image if you have the "Meeting Assistant Customization" Premium Add-On in your subscription.
If that is enabled, you can then visit this page:
Once there, select "Customize" on the top right of the page.
You can then update the name and upload an image you want to have as your assistant image when joining calls.
Once you hit saved, Speak will update your assistant!