From your grid’s admin preview, select “Edit Post Meta” for one of your Grid items.

Next, select an alternate skin for the item.
Post-based Grid view:

Custom Grid view:

Result:

Alternate Item Skins
Essential Grid WordPress Gallery Plugin
Inject life into your websites with breathtaking galleries built using Essential Grid
From your grid’s admin preview, select “Edit Post Meta” for one of your Grid items.
Next, select an alternate skin for the item.
Post-based Grid view:
Custom Grid view:
Result: