This is sometimes called a 'smashed window'...
Onya
The area in which the red cross appears is actually a picture or a graphic. In the code that explains how the page should look, there are links to an image, usually in an image folder on the server.
When you come across this, it means one of the following:
1. The link to the image is incorrect
2. The image has been removed from the original location
3. The image has become corrupt
4. The image has not been saved in a web format
5. That you have 'Display Images' switched off in your web browser (presume this doesn't apply as you don't mention that you're not getting images)
In summary, it usually means one of 1 - 4 above, and that basically the site you visited is poorly maintained. There's is nothing you can do about it as a visitor to a website.
atb
Cello