How to detect touches on UIImageView of UITableViewCell object in the UITableViewCellStyleSubtitle style

In your cellForRowAtIndexPath method add this code

cell.imageView.userInteractionEnabled = YES;
cell.imageView.tag = indexPath.row;

UITapGestureRecognizer *tapped = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(myFunction:)];
tapped.numberOfTapsRequired = 1;
[cell.imageView addGestureRecognizer:tapped];   
[tapped release];

And then to check which imageView was clicked, check the flag in selector method

-(void)myFunction :(id) sender
{
    UITapGestureRecognizer *gesture = (UITapGestureRecognizer *) sender;
    NSLog(@"Tag = %d", gesture.view.tag);
}

The accepted solution is currently broken in iOS 5.0. The bug causes the image view's gesture recognizer to never be triggered. Through research on the official developer forums I found that this is a known bug in iOS 5.0. It is caused by an internal implementation that causes -gestureRecognizerShouldBegin: to return NO. The bug appears when you are setting the gesture recognizer's delegate to the custom UITableViewCell subclass itself.

The fix is to override -gestureRecognizerShouldBegin: in the gesture recognizer's delegate and return YES. This bug should be fixed in a future version of iOS 5.x. This is only safe as long as you are not using the new UITableViewCell copy/paste API's.

- (BOOL)gestureRecognizerShouldBegin:(UIGestureRecognizer *)gestureRecognizer
{
    return YES;
}

For Swift, in your cellForRowAtIndexPath method add this code

cell.imageView?.userInteractionEnabled = true
cell.imageView?.tag = indexPath.row

var tapped:UITapGestureRecognizer = UITapGestureRecognizer(target: self, action: "TappedOnImage:")
tapped.numberOfTapsRequired = 1
cell.imageView?.addGestureRecognizer(tapped)

And then to check which imageView was clicked, check the flag in selector method

func TappedOnImage(sender:UITapGestureRecognizer){
    println(sender.view?.tag)
}