@munawar1235: nice article. But I would like to mention some points about the license attribution of images. Three things are always necessary(or it is a good practice to do so):

• Link to the source image (like the flickr link / wiki link)
• Username of creator/uploader and link to their profile (if available)
• License attribution link (if CC-by-SA Ver2 please provide that link). An example below. :
  Image Source: Flickr, Uploader: ch00n, License: CC BY 2.0

So I don't know if you noticed this: The first figure which you have used has a license valid to use commercially till 2017. So these are subtle points. Luckily your picture is from 2008 as I understand, so it is of no issue. But please do background check always.