Hi Aftab,
Thank you for your prompt reply.
My issue is that I do not see the Media Libray as shown in your screenshot-21.
In my case when I click the Set Feature Image I get this,
https://www.ppnet.gr/new/wp-content/uploads/2016/05/addbutton1.png
and when I click “show” next to the image I want to select I get this,
https://www.ppnet.gr/new/wp-content/uploads/2016/05/addbutton.png
There is no “Set Feature Image” option there.
Forgive my ignorance in these, I am really new in WordPress.
Thank you again,
Evi