I’m having a bit of trouble following.
Your problem is landscape images on mobile, correct? As far as I know, landscape images are responsive. They scale and don’t get cut off.
The topics linked address extra long portrait images. Which is where I’m a little bit confused 
Are you seeing the issue on your phone or in browser dev tools? Is there anyway you can upload an image like you described here? If I get the same result and there’s anything that I know how to do about it with CSS I’ll help