I\'m trying to do a simple thing; read an image from the internet, save it to the app\'s documents directory on the iphone, and read it back from that file so that i can do
Definitely give memory management rules a quick review. Nothing jumps out that would cause the error you're getting, but you're leaking all those objects your allocating. If you don't understand the retain/release pattern, chances are there's another spot in your code where you're not retaining an object properly, and that's whats causing the EXC_BAD_ACCESS error.
Also note that NSString has methods for dealing with filesystem paths, you should never have to worry about the separator yourself.