add last image

3.1-collab-vers-github.md

@@ -14,7 +14,7 @@ Even if you’re working alone, you’re probably going to make lots of changes
 
 You might make multiple copies of your files to preserve a version that's working while you try to improve it or add functionality, but keeping track of all these versions and the differences between them becomes difficult.
 
-![repo image](https://raw.githubusercontent.com/mozillascience/study-group-onboarding/blob/master/images/gh06.png)
+![repo image](https://raw.githubusercontent.com/mozillascience/study-group-onboarding/master/images/gh06.png)
 
 **You need version control.** Imagine your document has a life story. Version control is like a time machine, it can take you back to the moment your document was born, or any other point in time when you or a collaborator saved that document. **You don’t save copies of your document, you just save the the life story of the document, or its timeline.**