There are 2 reasons for why the image zoomed and cropped:
1a) the parallax effect need to bigger the image in BMslider, or the image will generate pitch with bottom of the wrap. We’ll try to add a forbid parallax option in future releases;
1b) the slider image is fit the browser window size automatically because it is fullscreen, so it would be cropped and zoom-out or zoom-in. It is impossible to completely original size display. Did you mean that want the image shown completely(no cropped)? Please make sure, i’ll make some test and let you know the way.
If you forbid the parallax-Y, it would be better, please follow:
– download the file, unzip it
– login FTP, go to wp-content ▸ themes ▸ theone ▸ functions ▸ theme ▸ plugins
– upload / replace ux-bmslider.php