For some reason, I can't change the nextArrow and prevArrow settings in [Ken Wheeler's Slick carousel](http://kenwheeler.github.io/slick#settings) -- I'm trying to replace the standard arrow icons with SVG files I have saved in the same directory as the slick-theme.css file. I've been attempting to keep the `<button>` tags intact to preserve functionality, and putting the svg file in an `<img>` tag where 'next' and 'previous' currently exist, but it isn't yielding any results. How do I fix this? Defaults are as follows, as part of a settings object:

`prevArrow: '<button class="slick-prev" aria-label="Previous" type="button">Next</button>',
 nextArrow: '<button class="slick-next" aria-label="Next" type="button">Previous</button>'`