Screen Resolution Studio 1557

I have a Studio 1557 with the HD screen running Win 8.1. Recently I installed the Bionix Wallpaper Changer software that I also run successfully on my desktop. Surprisingly, on the laptop the program always tiles the background because it thinks the screen resolution is less than 1920 x 1080. It reports the resolution as 1536 x 864. The software author sent me a "ruler" which indeed reported the lower resolution. Are there TWO resolutions on my laptop?