The problem with the images is that they don’t have the same ratio as the slider does. For example your seo-ok-1024×512.jpg image is 1024x512px and the slider in my fullHD screen is 1903x696px.
What you can try is changing your slider’s size at the Edit slider -> Slider size to match the ratio (you can try using your image’s size), but I think that would be pretty large in fullHD, so that might not be the solution for this.
Or you can modify the Edit Slider -> under Slides: Resize slide background to contain mode (you can read the documentation on this option here: https://www.nextendweb.com/wiki/smart-slider-documentation/slider-settings/#resize ) which will keep the image ratio.
Or if you meant the blurriness, that is happening because the images you are using are smaller than the slider (if you are viewing the slider in a larger monitor) and the image scaling usually causes them to be blurry.