Is there any difference between writing an objects(ex array types and NSObject types) to plist and NSFileManager.
if so can i write 1000's of images data and mp3 songs to plist.
NSFileManager is used to do things like copy a file, remove a file, and move a file. You wouldn't use NSFileManager to write out a new file. It's only good for working with existing files. It isn't comparable to a plist in the sense of using a plist vs. NSFileManager.
However, if the question you're trying to answer is should I store all my data in a plist or in separate files then that depends. If you're going to store 1000s of images and mp3s, then you definitely do not want to store them all in a single plist. Plists are an inefficient format for storing and updating large amounts of information, both in terms of speed and memory. For example, if you wanted to update a single string in your plist, you have to read the entire plist into memory, update it, and then write the entire plist back to disk. You cannot update just a portion of the plist using the standard plist functions provided by Foundation. If your plist contains all your image and mp3 data, it's going to be really slow.
You may be able to get away with using a plist as a manifest for your images and mp3s which are stored as separate files on disk, but even that can get slow. I'd recommend using SQLite or Core Data instead for the manifest of files and then keeping each image and mp3 as a separate file in the file system. Or, if you don't need to store any metadata with each item, you don't need the manifest at all. If you do end up going with a plist for your manifest, make sure to save the plist as a binary plist using the NSPropertyListBinaryFormat_v1_0 option. This will make the plist take up less space on disk and de-serialize faster when you read it again.