In many cases, animation transitions are already coded into your theme so that when a page resizes, elements on the page move smoothly to their new positions. If this is true, the grid will animate smoothly when you resize your window. Enabling this in the widget will enable transitions when your theme lacks them or override them with the default animationduration value where they do exist. This setting should overwrite any existing transitions. If you see the grid animating twice, set animate to false or modify your css.
This setting defaults to true in the widget and free plugin.
Animationduration is not available in the widget, but is available in the shortcode.
This value defaults to .7s and the value must be in time format.
[featured_image_pro animate=false posts_per_page=4]
Grid with default plugin transition duration of .7s
[featured_image_pro posts_per_page=4 animate=true]
Grid with modified transition duration of 1s
[featured_image_pro posts_per_page=4 animate=true animationduration='1.0s' ]