Update: For Question #3, What Norman provided was the one provided by SAP as well. You need to upload your logo in the intranet. However please note that:
1. There should be no closing tag. In HTML, the <img> tag has no end tag.
2. Image URL is not a path to the local machine. If in any such cases you like to use image from the local machine, location should be specified via UNC (\\server\folder\folder\file)
I am closing now this thread. Thanks for all the help guys.
All the best,
Santi