Use the URL of your Procurios platform to show the images in the preview.
Svg images are not supported and don't forget to change the "Base url for images (for preview)" field to the link of your Procurios platform so that the images are shown in the preview. The image must be present in your library.
Left: displays logo left + subject right. Center: displays only logo centered, no subject.
For good quality images for retina screens, always use images that are double the size of the logo width.
The default token is the same as unsubscribe. You can set your own tokens in your Procurios platform at Mailings > Settings > Profile/Unsubscribe. Next you set the value of this field to the newly created token.
You can set the standard default form of this token in your Procurios platform at Mailings > Settings > Profile/Unsubscribe
In case of an e-mailaddress, use mailto: as prefix