The NextGen Nivoslider plugin allows you to create a NivoSlider, using images from your NextGen gallery, with a simple shortcode or widget.
Itís a plugin that allows you to use a NivoSlider in WordPress by using a shortcode. It allows you to populate the NivoSlider with images pulled from your NextGen Gallery by gallery ID, image tags or simply everything!
You may need to give TimThumb's cache folder permissions by using CHMOD 775.
In order for the effects to work the max-width of ".nivoSlider img" needs to be none. By default this will be set as !important, however it might be that you altered the CSS and that another stylesheet is overriding the style.