The picture of the Buddha represents Nirvana because the final goal of Buddhism is to reach Nirvana which is a transcendent state in which there is no suffering, desire, nor sense of self, and the subject is released from the effects of karma and the cycle of death and rebirths.

 Looking at koalas make me happy. I think they are really cute and anytime is see a picture of them they bring me complete happiness.
The disney castle represents happiness to me because a lot of people choose to travel there every year. They take pictures outside the castle with loved ones and have huge looks of joy on their faces. The company of disney puts out a ton of tv shows and movies that people of all ages can enjoy.
The people in this picture are the band Nirvana. Most are probably wondering how they connect to the definition of Nirvana. Well the bands music brings joy to so many people in life, including my best friend. She loves everything they stand for, overtime she's in a sad mood she turns on their music and is overcome with joy.