Disable right click on selected images in Joomla

Hello Bidders, I want a running script which can disable right click on selected image in Joomla. For example if there are 10 images in a page I want 5 images downloadable by right click of the mouse and rest 5 should have right click disable. The code must be written either in php or javascript. It must be integrated in joomla. Need to see the demo before awarding the [login to view URL] will be released immediately after that. *Urgent :Needs to be done in next 24 hours. Lower bid will be given preference. Just 1-2 hour job. Thanks