Preview not showing images or stylesheet

[testsetup]

This has been asked before but I cannot see a solution in the forums.

I am using the latest version and images and my stylesheet are being shown when using the editor.
I click preview and every bit of styling/ images are lost.
In the header of the page I am editing is this link to the stylesheet:
 <link rel="stylesheet" type="text/css" href="tgc.css" />

Does someone have the solution please?

[admin]

Hello,

I will reply to your email directly and try to figure out this problem.