H. Peter Pfeufer

The NextGEN widgets only allow showing of single images, I needed a solution to show links to galleries, so I wrote this widget. You can specify the following parameters:
<ul>
<li>Maximum Galleries: the number of galleries you want to show</li>
<li>Gallery Order: you can select random, date added ascending or date added descending</li>
<li>Gallery Thumbnail: which image should be taken as thumbail in the sidebar (preview set in NGG, first or random image)</li>
<li>AutoThumb parameters: if you got <a href="https://wordpress.org/extend/plugins/autothumb/" rel="ugc">AutoThumb</a> installed, the widget will use its functions to resize the image to your needs. Use a string like <code>w=80&h=80&zc=1</code> here to show 80×80 square thumbnails.</li>
<li>Output width/height: if you don’t use AutoThumb, the plugin will set the HTML attributes width & height.</li>
<li>Default Link Id: the widget assumes that you set up pages for each gallery and link the gallery to that page (you can use the NGG Gallery Editor to do this). If a gallery has no link set, it will use the default link (id of a page or post).</li>
<li>Exclude galleries: exclude galleries by specifying their ID as comma separated list</li>
</ul>

NGG Sidebar Widget

A widget to show NextGEN galleries listed in your sidebar.

Aldert Vaandering

NextGen NivoSlider allows you to create a <a href="http://nivo.dev7studios.com/" rel="nofollow ugc">NivoSlider</a> as a widget or with a shortcode. 
This plugin uses the ‘NextGen Gallery’ plugin to obtain the images using tags or gallery IDs.
NivoSlider is a great responsive image slideshow that is highly customizable. With a large array of effects and many additional options you are sure to find a combination that will suit your website.
Requirements:
<ul>
<li><a href="https://wordpress.org/extend/plugins/nextgen-gallery/" rel="ugc">NextGen Gallery Plugin</a></li>
</ul>
Features:
NextGen NivoSlider has been completely overhauled and is continually being added to. It currently supports all the of NivoSlider’s original functions and even has some extra’s!
<ul>
<li>Responsive!</li>
<li>Fully integrated with NextGen gallery</li>
<li>Theme support</li>
<li>Automatic URL linking (put a mailto:, http://, ftp:// or local / into your alt text)</li>
<li>Extra effect(s)</li>
<li>Shortcode and Widget support</li>
<li>Touchscreen support (experimental)</li>
</ul>
Parameters:
You can use the following parameters in the [ngg-nivoslider] shortcode. 
Defaults, where applicable, are shown between parentheses (), available options between brackets [].
<ul>
<li>title: Title for slider. Leave blank for no title. (ex: title=”My Slider”)</li>
<li>gallery: Leave blank to use all galleries or choose a gallery to use. (ex: gallery=”galleryid”)</li>
<li>order [random”|”asc”|”desc”|”sortorder”]: Order to display results in. You can choose; Random, Latest First, Oldest First, or NextGen Sortorder. Random will still work when a page is cached. (ex: order=”random”)</li>
<li>tags: comma separated list of tags to filter results by. (ex: tags=”tag1, tag2″)</li>
<li>shuffle [boolean]: If order is random and this is true will shuffle images with javascript. Useful if your are caching your pages. (ex: shuffle=”true”)</li>
<li>max_pictures: The maximum amount of pictures to load. (ex: max_pictures=”6″)</li>
<li>html_id (“slider”): HTML id to use. Defaults to ‘slider’. Needs to be different for multiple sliders on same page. (ex: html_id=”custom-slider”)</li>
<li>width: Width to use on slider. (ex: width=”200″)</li>
<li>height: Height to use on slider. (ex: height=”150″)</li>
<li>center: Centers content in container. Requires width to be set. (ex: center=”1″)</li>
<li>resize: Resizes the images using TimThumb(v2). Available options are: (ex: resize=”3″) 
 1 – Resize to Fit specified dimensions (no cropping) 
 2 – Crop and resize to best fit the dimensions (default) 
 3 – Resize proportionally to fit entire image into specified dimensions, and add borders if required 
 4 – Resize proportionally adjusting size of scaled image so there are no borders gaps</li>
<li>resizewidth: The width TimThumb will use to resize the image (sc: resizewidth=”800″)</li>
<li>resizeheight: The height TimThumb will use to resize the image (sc: resizeheight=”600″)</li>
<li>resizebg (“ffffff”): The color (denoted in hex) to use for the borders that are generated when using resizing option 3 (ex: resizebg=”a0fb69″)</li>
<li>caption [“alttext”|”description”|”both”]: Show a caption with the slide, showing either the alttext or description as set up in NextGen gallery or both as “Bolded AltText – Description”</li>
<li>htmlcaption: HTML formatted caption to show on all images (ex: htmlcaption=”Title Welcome to <a>this website</a>“)</li>
<li>showgallerytitle [boolean]: Display the gallery title (ex: showgallerytitle=”true”)</li>
<li>showgallerydesc [boolean]: Display the gallery description (ex: showgallerydesc=”true”)</li>
</ul>
Nivo slider settings:
Please check the NivoSlider website for <a href="http://nivo.dev7studios.com/#usage" rel="nofollow ugc">more details</a>.
<ul>
<li>effect: What effect to use as transition. You can specify sets like: ‘fold,fade,sliceDown’. See list below for available effects.(ex: effect=”sliceDown,sliceUp”)</li>
<li>slices: The amount of slices to divide the image to for the slice effects(ex: slices=”3″)</li>
<li>boxCols: Amount of columns to split the image into for the box effects (ex: boxcols=”10″)</li>
<li>boxRows: Amount of row to split the image into for the box effects (ex: boxrows=”8″)</li>
<li>animSpeed: Slide transition speed in milliseconds (1000ms = 1 second). (ex: animspeed=”300″)</li>
<li>pauseTime: Time to pause in milliseconds (1000ms = 1 second) before continueing to the next image (ex: pausetime=”5000″)</li>
<li>startSlide: Set starting Slide. It’s 0-index so use 0 for the first slide. (ex: startslide=”3″)</li>
<li>directionNav [“true”|”false”]: Whether to display the Next & Prev controls or not. (ex: directionnav=”true”)</li>
<li>controlNav [“true”|”false”]: 1,2,3… (ex: controlnav=”setting”)</li>
<li>controlNavThumbs [“true”|”false”]: Use thumbnails for Control Nav if set to true. (ex: controlnavthumbs=”true”)</li>
<li>thumbsWidth: Resize thumbnail to this width. Recommended to set if using thumbnails. (ex: thumbswidth=”20″)</li>
<li>thumbsHeight: Resize thumbnail to this height. Recommended to set if using thumbnails. (ex: thumbsheight=”20″)</li>
<li>thumbsContainerHeight: Height for thumbnails container. Calculation should be ‘number of thumbnail image rows’ x ‘thumbsheight’. (ex: thumbscontainerheight=”20″)</li>
<li>thumbsGap: Gap between thumbnails. (ex: thumbsgap=”5″)</li>
<li>controlNavThumbsFromRel: Use image rel for thumbs. (ex: controlnavthumbsfromrel=”setting”)</li>
<li>controlNavThumbsSearch: Replace this with… (ex: controlnavthumbssearch=”setting”)</li>
<li>controlNavThumbsReplace: …this in thumb Image src. (ex: controlnavthumbsreplace=”setting”)</li>
<li>keyboardNav: Use left & right arrows. (ex: keyboardnav=”setting”)</li>
<li>pauseOnHover: Stop animation while hovering. (ex: pauseonhover=”setting”)</li>
<li>manualAdvance: Force manual transitions. (ex: manualadvance=”setting”)</li>
<li>prexText: Text to display for previous (ex: prevtext=”prev”)</li>
<li>nextText: Text to display for next (ex: prevtext=”next”)</li>
<li>randomStart [“true”|”false”]: Start with a random slide (ex: randomstart=”true”)</li>
<li>captionOpacity: Universal caption opacity. (ex: captionopacity=”setting”)</li>
<li>disableCaptions: (ex: disablecaptions=”1″)</li>
<li>beforeChange: (ex: beforechange=”setting”)</li>
<li>afterChange: (ex: afterchange=”setting”)</li>
<li>slideshowEnd: Triggers after all slides have been shown. (ex: slideshowend=”setting”)</li>
<li>lastSlide: Triggers when last slide is shown. (ex: lastslide=”setting”)</li>
<li>afterLoad: Triggers when slider has loaded. (ex: afterload=”setting”)</li>
</ul>
Nivo Effects:
<ul>
<li>random</li>
<li>sliceDown</li>
<li>sliceDownLeft</li>
<li>sliceUp</li>
<li>sliceUpLeft</li>
<li>sliceUpDown</li>
<li>sliceUpDownLeft</li>
<li>fold</li>
<li>foldReverse</li>
<li>fade</li>
<li>slideInRight</li>
<li>slideInLeft</li>
<li>boxRandom</li>
<li>boxRain</li>
<li>boxRainReverse</li>
<li>boxRainGrow</li>
<li>boxRainGrowReverse</li>
</ul>
Shortcode examples:
<ul>
<li>[ngg-nivoslider html_id=”about-slider”]</li>
<li>[ngg-nivoslider title=”Hello” gallery=”1″ html_id=”about-slider” width=”200″ height=”150″ center=”1″]</li>
<li>[ngg-nivoslider html_id=”about-slider” directionnav=”false” controlnav=”false”]</li>
<li>[ngg-nivoslider tags=slideshow order=”random” effect=”fade” shuffle=”true” max_pictures=”12″ html_id=”slider” resizebg=”fdfdfd” resizewidth=”900″ resizeheight=”620″ resize=”3″ center=”1″ directionNav=”false” controlNav=”false” pauseTime=”10000″ animSpeed=”1000″ pauseOnHover=”false”]</li>
</ul>
<h3>To do</h3>
Feel free to suggest new features or things you’d like to see in this plugin!
<ul>
<li>Create some extra themes.</li>
<li>Scrollable thumbnails?</li>
</ul>

NextGen NivoSlider

This plugin does not taken title attribute in image which is bad for SEO. Also not working with updated version of NextGen gallery plugin. 

didn't work

The NextGen Nivoslider plugin allows you to create a NivoSlider, using images from your NextGen gallery, with a simple shortcode or widget.

NGG Sidebar Widget vs NextGen NivoSlider