Here is how to put an image in the right portion of a UITextField:
UITextField *textField = [[UITextField alloc] initWithFrame:CGRectMake(55, 10, 660, 30)];
textField.rightViewMode = UITextFieldViewModeWhileEditing;
UIImageView *imageView = [[UIImageView alloc] initWithFrame:CGRectMake(0, 0, 15, 15)];
imageView.image = [UIImage imageNamed:@"invalidFieldCircle"];
textField.rightView = imageView;
This also assumes that an image called "invalidFieldCircle.png" is in your project's "Resources" directory, which should be located just below the main project directory (you may have to create it).