Different image sizes for desktop and Mobile

Hi there,
I am having a hard time figuring out how to change the image size (aesthetically) for desktop yet main the size on mobile.
When I insert a vertical image into a block, the image is too big on desktop. I need the vertical image to fit on the desktop screen. Thus, it can’t be stretched out too much. But when I change the size in desktop to what I need, the mobile version is affected.
I’ve been going back and forth from mobile preview to desktop and all I have done is arrange from one end but not the other and vice versa.
I hope all this makes sense.
Is there a way I can solve this issue without coding?

Thanks
James