The Jolly Roger is a flag with a skull and crossbones that was traditionally flown on a pirate ship, although many pirates would just fly a plain black flag. The reason pirates wanted people to know they were pirates was just to frighten the crew of other ships into giving up without a fight. The Jolly Roger in the picture is being flown along with some other modern flags.
You jot something down when you quickly write or draw it. The person in the picture is jotting down some notes.
A journey is a trip from one place to another, usually taken over quite a long time. The word journey can also be used to describe progress from one state to another, for example a weight loss journey. The people in the picture are on a bike journey. A similar word to journey is travel or trek.
Jousting is a medieval sport where two people on horses run at each other on either side of a barrier. Each person wears armour and wields a lance. The object is to knock your opponent off his horse.
Jowls are the parts of your face around your jaw and neck, particularly when they are large and fatty.
A judge is someone who is in charge of a court of law, and listens to all sides of a court case, when someone has been accused of doing something bad. Judges also decide what punishment will be given to someone who is found guilty. Outside of a law court, a judge is someone who decides who will win a competition, such as a sports game, a pet show, or an art competition.
A jug is a container designed to pour a liquid like water or milk from. It has a handle to hold it with and a spout so that whatever is in the jug goes in the right place and doesn't spill and make a mess when you pour it.
Juggling is the art of throwing some objects through the air from one hand to another, in a loop. You can juggle with balls, small bean bags, rings, skittles, burning brands, knives or even chainsaws. Juggling is most often seen done at circuses or by street performers. The lady in the picture is juggling with three balls, the more skilled you are the more objects you can juggle at once.