As the title says, I would like to resize the display window during the execution.

In my program, every time I click on the window I can choose an image to display and I would like the display size fits every time the size of the image displayed.
Something like this:

2. PImage img;
3. 
   
4. void setup(){
5.   pickImage();
6. }
7. 
   
8. void draw(){
9. }
10. 
    
11. void mousePressed(){
12.     pickImage();
13. }
14. 
    
15. void pickImage(){
16.   String path=selectInput();
17.   img=loadImage(path);
18.   size(img.width,img.height);
19.   image(img,0,0,width,height);
20. }

But the display window size change only the first time! Any suggestions?