Hello,

As per the screen you have provided, you have enabled the “Use images from product variations” and I see the swatch takes the image.

Each variation has the main image and gallery, as soon as you add the main image for a variation it should be shown as soon as you chose: https://gyazo.com/960f60e93f9c1dbb4a588371f2bb1392

If you have any questions please feel free to contact us.

Best Regards