SharePoint 2013 - HidePrevious, Next, and Pause buttons on Picture Library Slideshow Web Part's

Add the Script Editor or Content Editor webPart and  paste below code.

<style>

.ms-WPBody a[onclick ^= "Next"]{

        display:none;

}

.ms-WPBody a[onclick ^= "Play"]{

        display:none;

}

</style>