Update 3 4 control perspective

3-4-control-perspective.md

 # Controlling perspective (and how to use Rendering Pane)
 
+<p align="center">
 ![](img/3-4-rendering-pane.png)
 
 After adding a new layer or selecting a layer from the list, **Rendering Pane** displays the meteorological data in the 3D-image and contains some options for controlling perspective.
@@ -16,6 +17,7 @@ In the **Rendering Pane**, the *polar coordinates* is set by default. You can ch
 
 The alternative way is to click the *Globe* button at the bottom-right corner of the program.
 
+<p align="center">
 ![](img/3-4-display-mode-compare.png)
 
 ### Showing/Hiding Legend and Color Bar
@@ -81,6 +83,7 @@ The *Color Bar* shows the variable names and units of the selected variable.
 
 You can right-click the *Legend* or the *Limit Range* to speed up the setting options for the layer.
 
+<p align="center">
 ![](img/3-4-right-click.png)
 
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