You can customize your gallery layout. Available layout options depends on the style of gallery you are using. For example, if you are using the Grid gallery, you will find the options to customize your gallery's column and row spacing, the number of columns and rows to be displayed as well as the theme of the bullets. 

To customize your gallery's layout:

1. Click on your Gallery to open the Gallery panel. 

2. Click Layout.

3. You will find the available options for your gallery on the Layout panel.

For example, if you have a Grid gallery, you will see the following settings on the Layout panel. Use the sliders to customize each of the options.