How to have a button's image not stretched to the button's dimensions?

I want to have a button with an image, but I can’t get the image not to be stretched to the button’s dimensions. I want it to stay with the original aspect ratio.

Button is the purple in the bottom, image is stretched (originally a square), how can I stop this from happening?

Put the button in an arrangement, and set image to Arrangement background. Should work. Button needs to be transparent for this to work.

Better way: use a clickable Image component.