I was wondering if anyone could suggest the best way for me to store images for my app.
I want to be able to provide an XML update functionality that will allow the
You can write to the filesystem, every app in iOS is sandboxed and has access to his own documents folder.
I would suggest to write on filesystem and only save the urls on the database as that is more performant than saving blobs on a database.
Apple has a good write up about the iOS filesystem.
Alternatively you could implement a solution using SQLite, Apple mentions it in the: Large Data Objects (BLOBs) section here:
https://developer.apple.com/library/mac/documentation/Cocoa/Conceptual/CoreData/Articles/cdPerformance.html#//apple_ref/doc/uid/TP40003468-SW5