I just tested on an Android device with a 6.5 screen. It does give the option for Large Icons, but I think this is an option that should not be available as using it has no benefit on small displays.
I think the issue you are seeing is a result of the aspect ratio on the phone and what you are displaying are different. The images displayed on the phone will be the same aspect ratio that you are displaying to the screen. So once the top and bottom of the image hits the sides of the phone display, they will not get any larger. To make them get larger, would mean cutting off part of what is being displayed, which could mean the text.
I hope this clarifies things.