I'm using Apache and I have a sample web folder on my Local Host, like:
      http://localhost/test/
Files in the test folder:   
     index.html  
     sample.jpg  
     .htaccess  
Sample source of index.html:
<html>
  <body>
    <img src="sample.jpg" />
  </body>
</html>
When I run the website at http://localhost/test/, it will simply show the image `sample.jpg' on the page.
Problem:
- I want to prevent the image showing as 
http://localhost/test/sample.jpgdirectly in the url bar. 
Note: I found that the solutions below work when tested on every browser except Firefox.