Both of my lateral incisor teeth are much smaller than the rest of my teeth. How can I fix this? (photos)

Having small or misshaped lateral incisors is quite common. In fact, humans are evolving to have smaller faces, and many people are missing one or both upper lateral incisors. So you're just further down the evolutionary chain!
From the picture you sent, it looks as if your laterals are narrow as well as very short in relation to your other front teeth. Having smaller laterals makes your front teeth look a lot bigger and wider. Your upper left canine is rotated not allowing for much room and looks to be darker in color. I would recommend a minimum of 6 porcelain veneers. This will help balance the symmetry and color of your smile

Hi:Lateral incisors generally are smaller than the centrals and the canines.  However, in your case the laterals are smaller than normal.  You have two basic options:1.  Porcelain veneer on the laterals incisors to bring them out a bit and make them larger2. 6 Porcelain veneers to distribute the width so that the lateral become as big as possible.Best,Dr. Maddahi

Yes this can absolutely be fixed. Either 2 veneers on the lateral teeth and possibly some recontouring on the 2 central teeth. Or to have everything look perfectly uniform we often do 4 upper front veneers. There are definitely options here!