We'd be happy to help point you in the right direction for this! The logo shown in your Unsubscribe Form is based on the logo in your Update Profile Form. You can access this form through the Landing Pages and More link found under the Sign-up Forms tab of your account.
Once you open this Update Profile Form, the Form Appearance section is where you can update your logo.
Frankie P. Community & Social Media Support
Did I answer your question? If so, please mark my post as an "Accepted Solution" by clicking the Accept as Solution button in the bottom right hand corner of this post.