How to glue buttons to the edges of the slider image?

Question

HTML

Fellow front-end developers, please tell me how to magnetize the buttons to the edges of the image so that when the resolution is changed, they do not move to the sides? I use the Slick slider.
Link to high rez img - https://drive.google.com/open?id=0B7RKfjb4iAEPSnpW...

Answer 1

Left button: left: 0 - btnWidth/2 px;
Right button: right: 0 - btnWidth/2 px;