Drupal iOS SDK - Can't get image to attach to node?

I'm building an app using the Drupal iOS SDK, and at the moment, I'm trying to make it so that my user can take a photo of something using the camera, save that image, upload it, and attach it to the newly created node. The image saves and uploads to my server just fine, and a node is created with my title and body fields, however I can't seem to get the image to attach to the created node (field_photo). Note: The field type is "image". See code below:

CameraViewController.m

- (IBAction)saveButton:(id)sender {

    NSMutableDictionary *nodeData = [NSMutableDictionary new];
    [nodeData setValue:_itemName.text forKey:@"title"];     

    NSData *imgData = UIImageJPEGRepresentation(self.imageView.image, 0.5);

    NSMutableDictionary *file = [[NSMutableDictionary alloc] init];
    NSString *base64Image = [imgData base64EncodedString];
    [file setObject:base64Image forKey:@"file"];
    NSString *timestamp = [NSString stringWithFormat:@"%d", (int)[[NSDate date] timeIntervalSince1970]];
    NSString *imageTitle = _itemName.text;
    NSString *filePath = [NSString stringWithFormat:@"%@%@.jpg",@"public://stored/", imageTitle];
    NSString *fileName = [NSString stringWithFormat:@"%@.jpg", imageTitle];
    [file setObject:filePath forKey:@"filepath"];
    [file setObject:fileName forKey:@"filename"];
    [file setObject:timestamp forKey:@"timestamp"];
    NSString *fileSize = [NSString stringWithFormat:@"%lu", (unsigned long)[imgData length]];
    [file setObject:fileSize forKey:@"filesize"];


    [DIOSFile fileSave:file success:^(AFHTTPRequestOperation *operation, id responseObject) {
        NSLog(@"File Saved!");

       [file setObject:[responseObject objectForKey:@"fid"] forKey:@"fid"];
       [file removeObjectForKey:@"file"];


    } failure:^(AFHTTPRequestOperation *operation, NSError *error) {
        NSLog(@"Failed to save file!");
    }];


    NSDictionary *bodyValues = [NSDictionary dictionaryWithObjects:[NSArray arrayWithObjects:_itemDescrip.text, nil] forKeys:[NSArray arrayWithObjects:@"value", nil]];
    NSDictionary *languageDict = [NSDictionary dictionaryWithObject:[NSArray arrayWithObject:bodyValues] forKey:@"und"];
    [nodeData setObject:languageDict forKey:@"body"];


    NSDictionary *fidLangDict = [NSDictionary dictionaryWithObject:@[file] forKey:@"und"];
    [nodeData setObject:fidLangDict forKey:@"field_photo"];
    NSLog(@"%@",fidLangDict);

    [nodeData setObject:@"storage_item" forKey:@"type"];
    [nodeData setObject:@"und" forKey:@"language"];

    [DIOSNode nodeSave:nodeData success:^(AFHTTPRequestOperation *operation, id responseObject) {
        NSLog(@"Item successfully added to Database!");


    } failure:^(AFHTTPRequestOperation *operation, NSError *error) {
        NSLog(@"Failed to add item to database!");
    }];