问存储大量图片和MP3歌曲iOS Sdk的最好方法是什么？

EN

//Store Image/Songs files to Application Directory
+(BOOL)writeToFile:(NSData *)data fileName:(NSString *)fileName {

    NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
    NSString *documentsDirectory = [paths objectAtIndex:0];

    // the path to write file
    NSString *appFile = [documentsDirectory stringByAppendingPathComponent:fileName];

        return [data writeToFile:appFile atomically:YES];
}
//Image/songs -  Retrieve from Application Directory
+(NSData *)readFromFile:(NSString *)fileName {

    NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
    NSString *documentsDirectory = [paths objectAtIndex:0];
    NSString *filePath = [documentsDirectory stringByAppendingPathComponent:fileName];

    NSData *myData = [NSData dataWithContentsOfFile:filePath]; 
    if (myData) { 
        return myData;
    }
    return nil;
}