Every iNewsletter publication has its own logo. You can change this in the Publication settings
To add update a logo
On the Dashboard, click Settings > General from the left menu
Under the Logo section you'll see a grey + button. Click this to upload the logo
To change the logo
On the Dashboard, click Settings > General from the left menu
Place your mouse over the current logo and a pencil icon will appear. Click this to upload a new logo
To delete the logo
On the Dashboard, click Settings > General from the left menu
Click the grey delete icon at the top right of the current logo