Resize a button while it's active

I want to resize a button while it's being pressed. At the moment I have a style with no image as background (_style.normal.background = null) and Buttons are being drawn using some images and that style. I would like to define a size of the buttons being displayed for the same layer but in the active state instead of normal and I have no idea how to do it.

code:

 public class Buildings : MainSubPanel {
     private Rect[] _boxes;
     private GUIStyle _style;
     private Texture2D[] _icons;
     
     public Buildings(Swapper swapper, Texture2D[] icons) : base(swapper){
         int i = 0;
         int n = 0;
         int shift = 10;
         _icons = icons;
         _boxes = new Rect[12];
         _style = new GUIStyle();
         _style.normal.background = null;
         while(i < 3){
             while(n < 4){
                 _boxes[i*4+n] = new Rect(15+shift+shift*n+50*n, 15+shift+shift*i+i*50, 50, 50);
                 ++n;
             }
             n = 0;
             ++i;
         }
     }
     
     public override void draw(){
         int i = 0;
         while(i<_icons.Length){
             if(GUI.Button(_boxes[i], _icons[i], _style)){
                 _swapper.swap(i);
             }
             i++;
         }
     }
 }