There is a provision for adding custom lines or fields in the various forms, there is also an option to select as line text, paragraph, drop down, image and date.
How do I add image in the customised template
With HTML reference to an external URL. See the Guide: Manager Cloud. You cannot reference a location on your own machine. For example:
yields:
@Tut How do i make a image web accessible?
Store it on a server in the internet eg on a cloud server