Table View Scrolling Async

I am loading an image to a table view cell, each cell has an image. I've adapter a couple tutorials to the code below, but I am still having slow down.

I am loading these images from the documents directory. Any tips or ideas on how to speed this process up?

Edit Revised Code:

Beer *beer = (Beer *) [self.fetchedResultsController objectAtIndexPath:indexPath];
cell.displayBeerName.text = beer.name;

// did we already cache a copy of the image?
if (beer.image != nil) {
    // good.  use it.  this will run quick and this will run most of the time
    cell.beerImage.image = beer.image;
} else {
    // it must be the first time we've scrolled by this beer.  do the expensive
    // image init off the main thread

    cell.beerImage.image  = nil;   // set a default value here.  nil is good enough for now

    [self loadImageForBeer:beer atIndexPath:indexPath];
}
- (void)loadImageForBeer:(Beer *)beer atIndexPath:(NSIndexPath *)indexPath {

    dispatch_queue_t queue = dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_HIGH, 0ul);
    dispatch_async(queue, ^{

        UIImage *image = [UIImage imageWithContentsOfFile:beer.imagePath];
        beer.image = image;

        dispatch_sync(dispatch_get_main_queue(), ^{
            UITableViewCell *cell = [self.tableView cellForRowAtIndexPath:indexPath];
            cell.beerImage.image = image;
        });
    });
}