The problem occurred while adding images on Joomla pages which has "Search Engine Friendly URLs" enabled.
First load shows images perfectly but after refresh it disappears., because of wrong image path. Even if you put full path, it removes domain path and leaves only default images path, Which is not right while SEF urls enabled.
Here is how to fix it ( Solution ):
1. Go to Gobal Configuration -> System -> Cashe settings
2. Change to "No"
3. Go to Plugin Manager. Search for System Cashe or Cashe.
4. Change Enabled to "No".
Full forums topic about this can be fount here:
p.s. joomla 1.5 or others like 1.5.15, 1.5.20 and so on..