Email Templates, Email Templates tab, edit Default Emails, HTML Content tab, right-click on the broken image object and select Image Properties. For the URL, replace ($DATA.logoURL} with a full URL (http://domain/img.jpg) or a relative path (path/img.jpg). Save. Test. Do the same for the newsletter template. These templates are databased as so will survive a code upgrade. The invoice is at skinsSKIN_NAMEtemplatesprint.receipt.php.