Round Classes
The w3-round-small class adds a 2px rounded corner to an element.
The w3-round class adds a 4px rounded corner to an element.
The w3-round-large class adds a 8px rounded corner to an element.
The w3-round-xlarge class adds a 16px rounded corner to an element.
The w3-round-xxlarge class adds a 32px rounded corner to an element.
The w3-round-jumbo class adds a 64px rounded corner to an element.
Used on images: