6
Sounds strange...
Perhaps you can check by clicking with right mouse button on a red X and view properties.
Then you see the path.
Check the path, if the corresponding image is uploaded indeed.
You can also view source and then the corresponding directory.
I had a similar thing once when I made a few changes in a file in Dreamweaver. Dreamweaver changed the path.
Since then I open files with images in notepad...
Good luck and greetz,