How to center rear wheels in weel well

The person that I got the car from did move the springs inward with intensions on putting bigger tires on the car, I was the one that put the 275/60/15 on the car. Now that the spring box's are welded to the frame all ready I am not sure if I want to mess with moving the springs forward to fix this trouble, like I've said I don't mind getting smaller tires to fix once and for all. Here is a picture of the passenger tire, pictures shows distance from front of wheel well and rear of wheel well on the passenger side.

Passanger Side Behind Tire.jpg

Passanger Side Front of Tire.jpg