iso is an image but animage of a CD or DVD there is .img files for download over on the Raspberry Download page
When you think about it is the logical place to look.
I am sorry for the responses of my fellow Geeks the do all so often forget what it's like to be on that Noob end of the spectrum.
Some day if you stick with it you will move along the spectrum towards being a geek as long as you remember your roots you will write good copy.
Please forgive the geeks but it does no harm to remind them they are producing gibberish for the noobs
Noob is not derogatory the noob is just the lower end of the noob--geek spectrum being a noob is just your first step towards being an uber-geek
If you find a solution please post it in the wiki the forum dies too quick