Updated Multi session (markdown)

Multi-session.md

@@ -1,6 +1,6 @@
 We will process consecutively five input databases that contain data taken from a robot during five mapping sessions. Databases at 1 Hz (smaller size) and 10 Hz (high feedback) are provided of the same experiments with the respective RTAB-Map settings files. The databases were created from the ROS bags on [ROS](https://code.google.com/p/rtabmap/wiki/ROS#Multi-session_mapping) page by using [data_recorder](https://code.google.com/p/rtabmap/wiki/ROS#data_recorder) node.
 
-[[https://raw.githubusercontent.com/introlab/rtabmap/doc/Tutorials/MultiSession/3.png]]
+[[doc/Tutorials/MultiSession/3.png]]
 
 <img src="https://raw.githubusercontent.com/wiki/introlab/rtabmap/doc/Tutorials/MultiSession/4.png" alt="AZIMUT3" width="400">
 
@@ -36,7 +36,7 @@ There two differences between the two ini files:
 ## Set database source
 While in the Preferences dialog, select "Source" on the left. Scroll down, check "Database source" and select the first database downloaded (map1_1Hz.db or map1_10Hz.db). Odometry was saved in databases so leave uncheck "Ignore odometry". Now scroll up to "Input rate". Set 1 Hz if you downloaded the 1 Hz databases or 10 Hz if you downloaded the 10 Hz databases. Press "Ok" to close the dialog.
 
-[[https://raw.githubusercontent.com/introlab/rtabmap/doc/Tutorials/MultiSession/1.png]]
+ [[doc/Tutorials/MultiSession/1.png]]
 
 ## Clean output database and initialization 
  * Just to make sure to start with an empty database, do Edit -> "Delete memory" and then press "yes".