Added screenshots for GitHub webpage on contributing new content

Author: tlkh

CONTRIBUTION_DETAILED_GUIDE.md

@@ -4,6 +4,16 @@
 
 If you would like to contribute a change to one particular file (e.g. this markdown file), you can simply click on the pencil icon at the top right-hand corner to open up a browser-based editor to make the changes.
 
+![Editing a file](images/edit_file.jpeg)
+
 Of, if you would like to add a new file, click on the "Create new file" button when in a folder view. 
 
+![Adding a new file](images/add_file.jpeg)
+
 Then fill in the small form below the editor with some descriptions about the changes you made, and submit a Pull Request for approval. You will be able to follow the progess on the repository's "Pull Requests" tab.
+
+### 2. Contributing a new project
+
+```
+TODO
+```