My left eye is smaller than my right eye. What is wrong? (Photo)

The question you ask is an excellent one. You appear to have
a ptosis (drooping) of the eyelid. This is a medical condition that can be
corrected, but it will require a surgery. It is important to discuss this with
your parents and to make certain that they understand how it affects you. After
this I would recommend that you meet, with your parents, a specialist to review
all the options available to you. Be healthy and be well, James M. Ridgway, MD, FACS

It appears that you have ptosis in your photographs. You should be evaluated in person by an oculoplastic surgeon who can determine what your problem is and guide you with possible treatment options. If surgery is warranted, you should recover very quickly. Good luck.

There are two main conditions that make one eye look smaller than the other:1. The eyelid is droopy on one side more than the other2. One eye may be more sunken in or bulgy than the other.You need to have a detailed examination by an Oculoplastics/Orbital surgeon to figure out which is the likely scenario. These conditions are often surgically correctable.Good luck

By the look of the pictures, it seems that you may have a Ptosis of your left eye. This condition is easily correctable with surgery. You need to consult a specialist in eye surgery.