IPhone : Get contents of PFFile without caching

I'm working on an app that has a kind of 'stream'/'timeline'. In order to quickly load new data, I'm currently caching all the data the app receives.

However, I'm encountering a problems: I'm getting a PFFile with getDataInBackgroundWithBlock method of Parse, which automatically caches the content as well.

However, Since I can't write PFFile to disk, I'm also caching the data from the PFFile, like this:

for (NSMutableDictionary *event in copyEventArray) {
        // PFFile isn't easy to encode, but UIImage is, so whenever we encounter a PFFile, we convert it to UIImage
        id imageFile = [event objectForKey:@"img"];
        if([imageFile isKindOfClass:[PFFile class]]){
            [imageFile getDataInBackgroundWithBlock:^(NSData *imageData, NSError *error) {
                if (!error) {
                    UIImage *image = [UIImage imageWithData:imageData];
                    [event setObject:image forKey:@"img"]; // the PFFile is now replaced for an UIImage
                    NSData *eventEncodedObject = [NSKeyedArchiver archivedDataWithRootObject:event];
                    [archiveArray addObject:eventEncodedObject];
                    loopCount++;

                    if(loopCount == [copyEventArray count]){ // when done looping, save it all
                        NSUserDefaults *userData = [NSUserDefaults standardUserDefaults];
                        [userData setObject:archiveArray forKey:@"events"];
                        NSLog(@"save is done");

                    }
                }
            }];
        } else {
            loopCount++;
            NSData *eventEncodedObject = [NSKeyedArchiver archivedDataWithRootObject:event];
            [archiveArray addObject:eventEncodedObject];

            if(loopCount == [copyEventArray count]){ // when done looping
                NSUserDefaults *userData = [NSUserDefaults standardUserDefaults];
                [userData setObject:archiveArray forKey:@"events"];
                NSLog(@"save is done");

            }
        }

However, when I do this, there are actually 2 of the same images in cache..

How do I prevent using getDataInBackgroundWithBlock? If that's the only way to go about it, there should be a way to cache the other event data without the image itself, while still being able to connect the 2 when displaying the data.