Display image in Win Form selected from specific folder

I have a Win form where there will be a button and a picturebox. when button will be pressed system will navigate to the specified folder and user on selection of single image the same will be displayed on the picture box fully.

 

I got some coding but the issue is whole image is not fit into the picture box.

My requirement is whatever will be the size for the picture box the image must fit into that.

 

Thanks & Regards

Gautam Paul