Quick and dirty UIImageView with networking

UIImageView+Network.h

//
//  UIImage+Network.h
//  Fireside
//
//  Created by Soroush Khanlou on 8/25/12.
//
//

#import <UIKit/UIKit.h>

@interface UIImageView(Network)

@property (nonatomic, copy) NSURL *imageURL;

- (void) loadImageFromURL:(NSURL*)url placeholderImage:(UIImage*)placeholder cachingKey:(NSString*)key;

@end

UIImageView+Network.m

//
//  UIImageView+Network.m
//
//  Created by Soroush Khanlou on 8/25/12.
//
//

#import "UIImageView+Network.h"
#import "FTWCache.h"
#import <objc/runtime.h>

static char URL_KEY;


@implementation UIImageView(Network)

@dynamic imageURL;

- (void) loadImageFromURL:(NSURL*)url placeholderImage:(UIImage*)placeholder cachingKey:(NSString*)key {
	self.imageURL = url;
	self.image = placeholder;
	
	NSData *cachedData = [FTWCache objectForKey:key];
	if (cachedData) {   
 	   self.imageURL   = nil;
 	   self.image      = [UIImage imageWithData:cachedData];
	   return;
	}

	dispatch_queue_t queue = dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_HIGH, 0ul);
	dispatch_async(queue, ^{
		NSData *data = [NSData dataWithContentsOfURL:url];
		
		UIImage *imageFromData = [UIImage imageWithData:data];
		
		[FTWCache setObject:data forKey:key];

		if (imageFromData) {
			if ([self.imageURL.absoluteString isEqualToString:url.absoluteString]) {
				dispatch_sync(dispatch_get_main_queue(), ^{
					self.image = imageFromData;
				});
			} else {
//				NSLog(@"urls are not the same, bailing out!");
			}
		}
		self.imageURL = nil;
	});
}

- (void) setImageURL:(NSURL *)newImageURL {
	objc_setAssociatedObject(self, &URL_KEY, newImageURL, OBJC_ASSOCIATION_COPY);
}

- (NSURL*) imageURL {
	return objc_getAssociatedObject(self, &URL_KEY);
}

@end

I just googling around and see you code looks pretty good 👍

But I'm just doubt is it the problem if some of my UITableViewCell will going to load the same source of image at the same time right before the first one have been loaded and cache.

It would be nice if you can help clarify what will happen.