Getting Image from Url Objective C

Ok there's a couple of things wrong here:

1. The conversion from URL (url) to NSString (newImage) is incorrect, what the code actually does there is try to load the contents of "" into the NSString.

2. The -imageNamed method takes a string that is a path of a local file, not a URL as an argument.

You need to use an NSData object as an intermediary, like in this example:

the accepted answer asynchronous version worked very slow in my code. an approach using NSOperation worked light years faster. the code provided by Joe Masilotti --> objective - C : Loading image from URL? (and pasted below):

-(void) someMethod {
    // set placeholder image
    UIImage* memberPhoto = [UIImage imageNamed:@"place_holder_image.png"];

    // retrieve image for cell in using NSOperation
    NSURL *url = [NSURL URLWithString:group.photo_link[indexPath.row]];
    [self loadImage:url];
}

- (void)loadImage:(NSURL *)imageURL
{
    NSOperationQueue *queue = [NSOperationQueue new];
    NSInvocationOperation *operation = [[NSInvocationOperation alloc]
                                        initWithTarget:self
                                        selector:@selector(requestRemoteImage:)
                                        object:imageURL];
    [queue addOperation:operation];
}

- (void)requestRemoteImage:(NSURL *)imageURL
{
    NSData *imageData = [[NSData alloc] initWithContentsOfURL:imageURL];
    UIImage *image = [[UIImage alloc] initWithData:imageData];

    [self performSelectorOnMainThread:@selector(placeImageInUI:) withObject:image waitUntilDone:YES];
}

- (void)placeImageInUI:(UIImage *)image
{
    [self.memberPhotoImage setImage:image];
}

In Swift 3 and 4

let theURL = URL(string:"")
let imagedData = NSData(contentsOf: theURL!)!
let theImage = UIImage(data: imagedData as Data)
cell.theImageView.image = theImage

This will be done in the main thread.

And to perform the same in asynchronous/background thread

   DispatchQueue.main.async(){
      let theURL = URL(string:"")
      let imagedData = NSData(contentsOf: theURL!)!
      let theImage = UIImage(data: imagedData as Data)
   }
   cell.theImageView.image = theImage

Updating upon Jim dovey answer,[data release] is no longer required because in the updated apple guidelines. Memory management is done automatically by ARC (Automatic counting reference) ,

Here is the updated asynchronous call,

dispatch_async(dispatch_get_global_queue(0,0), ^{
        NSData * data = [[NSData alloc] initWithContentsOfURL: [NSURL URLWithString: @"your_URL"]];
        if ( data == nil )
            return;
        dispatch_async(dispatch_get_main_queue(), ^{
            self.your_UIimage.image = [UIImage imageWithData: data];
        });

    });