You may find that you are getting broken image links in test messages, even though the message looks fine withing preview screens. This is typically caused by using a web design program that removes the domain name when referencing image paths.
For example:
The logo graphic for your Email System is located at http://Email System.com/images/Email System_logo.gif

...but if the domain name was removed from the image path, it would appear as /images/Email System_logo.gif

Referencing images this way is common within web design programs, but some programs don't pick up on the design programs' format and interpret these graphics as broken links.
This problem is frequently experienced when you make modifications to the html in both your own web design program and the Email Markerting system html editor.
Placing the following tag at the beginning of your html (right after '<head>' ) will typically resolve this problem:
'<base href="https://www.domain.com/">'
(remove the apostrophes from either end of the tag when applying it to your html)
Replace domain.com with the domain name of the site that is hosting your images. Doing so will let the program reading the html to fill in the domain name in the image links.