Sometimes we need to use ISO files, but we don’t want to record a CD/DVD for that purpose. But mounting an iso file, without scripts, would be a little complicated for beginners, so it is best to install two scripts, one to mount and the other one to unmount. 
You simply have to download the files mount and unmount and install them in the nautilus. If you don’t know how to install scripts, visit this link.
This information was taken from this site:
http://ubuntuforums.org/showthread.php?t=87369
Mount ISO files with just 2 clicks