How do I change the profile picture of Send Mail As account?

I recently bought a domain and finally added it as "send mail as" for my gmail account. So I have my previous business email (with my logo) with the gmail tag and a new business email with my own @. but my business email with my own @ doesn't have a profile picture at all, not sure how to add it because when I go to the setting and profile picture is just shows my main account that the business email is attached too, not allowing me to change a picture.