Use iOS8 custom keyboard with Image

I am iOS application developer. I am working in iOS custom keyboard extension. I need to show some image in my custom keyboard, that I have already done. But tapping on that image the same image will be paste/send into the text area (UITextField or UITextView). I have done the below code for this:

 NSTextAttachment *textAttachment = [[NSTextAttachment alloc] init];
        textAttachment.image = [UIImage imageNamed:@"Gun.png"];      

 CGFloat scaleFactor = 10;
 textAttachment.image = [UIImage imageWithCGImage:textAttachment.image.CGImage scale:scaleFactor orientation:UIImageOrientationUp];
 NSAttributedString *attrStringWithImage = [NSAttributedString attributedStringWithAttachment:textAttachment];
 //[attributedString replaceCharactersInRange:NSMakeRange(6, 1) withAttributedString:attrStringWithImage];

 [self.textDocumentProxy insertText:[NSString stringWithFormat:@"%@", attrStringWithImage]];

But the image is not showing in the text area. It will be veryhelpfull for me, if I get any positive feedback. Thanks in advance.