Nick Halsey

This plugin creates a fullscreen slideshow that displays randomly-selected pictures from your media library. Designed to display pictures related to your business/organization in the background at an event or in your office, there is no need to configure any settings or controls. Image captions/descriptions are automatically displayed as well, and can be configured based on your needs.
Once activated, you can view the slideshow by visiting <code>http://yourdomain.com/slideshow</code>. All JPEG images will be displayed (since .jpg is best for pictures, while .png and .gif are typically used for graphics).
Please note that it is not currently possible to pause the slideshow or go back; the slideshow is not designed for personal viewing. However, clicking/tapping on the image will open its attachment page in a new tab, allowing images to be contextualized or edited easily.
The slideshow can also be embedded into your site via a widget or a shortcode.
You can control some options by adjusting the url of the slideshow. Parameters are controlled via query string (and widget options and shortcode attributes).
<ul>
<li><code>size</code> is the size of the image to load, either <code>thumbnail</code> (discouraged), <code>medium</code>, <code>large</code>, <code>full</code>, or <code>auto</code>, which uses medium or large depending on <code>wp_is_mobile()</code>.</li>
<li><code>year</code> is the 4-digit numeric year in which the images were published.</li>
<li><code>month</code> is the numeric month in which the images were published (between 1 and 12), typically but not necessarily used in conjunction with <code>year</code>.</li>
<li><code>mode</code> defines a subset of images to use, such as <code>featured</code> for featured images only.</li>
<li><code>captions</code> controls the captions display: either <code>auto</code>, <code>none</code>, <code>title</code>, <code>titlecaption</code>, <code>caption</code>, or <code>description</code>. Caption data is read from the image attachment post and can be updated in the media library.</li>
</ul>
Using all options, for example: 
http://example.com/slideshow?size=full&year=2014&month=4&mode=featured&captions=titlecaption
You can see it in action <a href="http://uscasce.com/slideshow" rel="nofollow ugc">here</a>.

Content Slideshow

This plugin creates a fullscreen slideshow that displays randomly-selected pictures from your media library. Designed to display pictures related to y …

daxiawp

Automatically add a picture watermark, can select text or pictures are two types. 自动给图片添加水印，可选择文本或图片两种类型。 
详情：<a href="http://www.daxiawp.com/dx-watermark.html" rel="nofollow ugc">http://www.daxiawp.com/dx-watermark.html</a>
<h3>Arbitrary section 1</h3>

DX-Watermark

The pictures automatically add watermark. 图片自动添加水印.

Content Slideshow vs DX-Watermark