Below are the necessary steps to update the logo of your affiliate program:
From your account dashboard, go to Programs > Programs
In the Programs page, find the program whose logo you wish to change and click the “Edit” button.
In the Program Details page, under the General section, you will find the “Program Logo” field where you can browse your files for the new logo and upload it. Please remember that the logo must be 150×40 pixels or smaller.
Once the new logo is uploaded, click “Save” at the bottom of the page.