The best dress for a pear shape is definitely wrap style dress, like the blue one. Keeping it simple in the torso is key! You will want something that will skim over your hips, nothing too clingy. The key for a pear is to balance out your shape.
Some other helpful tips I can suggest would be to wear a v-neck style dress. It will lengthen your torso and draw the eye to the top half of your body. By adding a belt to your dress it will showcase your tiny waist. Details on a dress, like the lace on the black dress will define and really show off your dainty shoulders. Also prints can help disguise problem areas, try to stick to one uniform print head-to-toe to streamline your look.
When choosing a dress be sure that it is the right length so you do not loose your leg and make yourself unproportionate in the dress. I am a pear shape and love to wear long dresses in the summer, halters are such a great dress for the pear! What ever dress you choose have fun and feel good in it!