Responsiveness of Images with Using Image Slider

I'm having difficulty with getting the mobile responsiveness of our images to work correctly with the image slider... i've tried all kinds of different CSS.  Can't seem to this thing to work correctly... It just looks like hell.

Using the Upfront editor, if I set the image to display correctly for with 315 px viewport, when I open up the view port, the image in question doesn't auto-scale correctly, I've been trying to get the responsiveness of the slider to work correctly with us albeit large images for hours. I've tried all the CSS tricks i know. If it looks good in one viewport setting, it doesn't display correctly in a different viewport setting.

If you then set the viewport to default at 1080, the images then stretch to fill the viewport horizontally while maintaining the vertical size of the tablet view port.  How cookoo is that?