docs(examples): fix example img (#4678)

Author: sanskarjha

docs/examples/attachments.md

@@ -111,7 +111,7 @@ client.login('your token here');
 
 The results are the same as the URL examples:
 
-![Image showing result](/static/attachment-example1.png)
+![Image showing result](/static/attachment-example2.png)
 
 But what if you have a buffer from an image? Or a text document? Well, it's the same as sending a local file or a URL!