Seals and sea lions have many similarities, and are in the same family of Pinnipeds, but they lead very different lives. Seals are smaller than sea lions; male Stellar sea lions can grow to be up to 2,200 pounds. Seals also are suited to spend more time in the water than sea lions, which can "walk" on shore with their large flippers and spend time in large social groups. Another give-away is that sea lions have external ear flaps, whereas seals don't have external ears—if you look closely you can see tiny ear holes.
These two are sea lions. (See the ear flaps?)