To change the agency logo:

Click on the menu in the very top right corner of the screen and go to 'Setup'

Next, navigate to 'Agency Settings' then 'White Label'

To change the account logo:

Click directly on any of the account rows to open its settings menu

Click on 'Settings' towards the top-right of the page

Navigate to the 'Account' menu

The new account logo can be updated and used for the account's reports and dashboards.  The recommended size for your account logo is 300x90 px and up to 1MB in file size.

To change the thumbnail icon shown for each account under the 'Accounts' tab, upload a new company icon. Recommended size for the company icon is 45x45 px image up to 500KB in file size.