Update 3 2 open data

3-2-open-data.md

@@ -13,6 +13,7 @@ To open a file or a directory containing multiple files:
 
 The **Variables Pane** consists of two components: control bar and display area. After opening data files, the **Variables Pane** displays a hierarchical tree structure (*File Name* -> *Category Name* or *Vertical Coordinate System* -> *Variable Name*) of the variables in your data. 
 
+<p align="center">
 ![](img/3-2-2-variables-pane.png)
 
 By default, the variables are grouped by category and displayed with ID. You can customize the options to display variables as follows:
@@ -21,28 +22,34 @@ By default, the variables are grouped by category and displayed with ID. You can
 
 *  You can group variables by clicking *Grouping* button.
 
-   ![](img/3-2-2-variables-grouping.png)
+<p align="center">
+![](img/3-2-2-variables-grouping.png)
 
 *  You can display name or ID of variables by clicking *Text* button.
 
+<p align="center">
 ![](img/3-2-2-variables-text.png)
 
 *  You can filter variables by clicking *Filtering* button .
 
+<p align="center">
 ![](img/3-2-2-variables-filtering.png)
 
 *  You can click the *Arrange By Name* button to arrange variables by their name (with *A to Z* order).
 
+<p align="center">
 ![](img/3-2-2-variables-arrange.png)
 
 * If you want to close a data file, select that data file by click the file name on variable list, then click the *Close Dataset* button, then click *OK* button on the dialog box.
 
+<p align="center">
 ![](img/3-2-2-variables-close.png)
 
 ##### Speed up by right-click
 
 To customize options for displaying variables in a data file, select the file name and right-click, then select the options.
 
+<p align="center">
 ![](img/3-2-2-variables-right-click.png)