Images are loaded in the Media Browser or are integrated in the content at campaign setting. Images are stored under a certain path, which depends on how you arrange the images in your Media Browser. The path can be e.g.:

http://media.promio-mail.com/12391/pics/newsletter/bild1.jpg

The image is therefore in the newsletter folder and is called bild1.jpg. Now change the image path by moving the images, the path specified in the newsletter does not change. Thus, the image can not be displayed because it is not available in the folder.

When you set up images in the newsletter, make sure that the images will not be moved later.