Add images for example post.
Fix bug in org-blog-get-blog-from-filename.

When expand-file-name gets two paths, the former overwrites the latter.
We don't want this.
Remove (print..)'s.

There are still some debugging (print..) and and (message..)
commands around.  Deleting those in
org-blog-get-blog-project-from-filename after testing and fixing
bug.
Add Blog URL (and automatically) Blog Post ID.

Necessary information for posting without configuration alist.