[Plugin: Featured Articles Lite] Image always resized to 300px doesn't fit slider

Have you tried setting the image size to the size you want in the slider? The plugin won’t resize your images or do anything like that, it simply asks WordPress for the size you set on thumbnail size in admin. So if, for example, you want to use theme Smoke and your slider is set at let’s say 900×500 px, the image size should be same as the slider size. I know it isn’t very intuitive, at the moment we’re still working on the next update and this issue for background images (and not only) will be solved in a more user-friendly way.