<p class="cmb_metabox_description"><strong>Fill</strong> scales image to completely fill slider container (recommended for landscape images)</p>
<p class="cmb_metabox_description"><strong>Fit</strong> scales image to fit the container (recommended for portrait images)</p>
<p class="cmb_metabox_description"><strong>Fit if Smaller</strong> scales image to fit only if size of slider container is less than size of image.</p>
<p class="cmb_metabox_description"><a target="_blank" href="http://bit.ly/slider-image-scaling">Visual explanation</a></p>