how to change the source of images?

I use JavaScript to change image source based upon a user's click. Some images are missing though link in property is correct. On clicking same command, missing image is shown but previously displayed image is missing. Any advice on the resolution?

• Answer:

  It sounds as if you are trying to make a roll over . Either you, have forgotten to specify a default image or you have misspelled or left out an image in the script itself. Check your script and your links to make sure all have src images specified, and all spellings match those of the actual image files. it is amazing how often this happens because the fingers keyboard faster than the brain registers....