ChrisHurst

MyWebsiteAdvisor

This plugin allows you to Automatically add a watermark to all images as they are viewed on your WordPress Website. 
Watermarks are not permenant, original images are not edited. 
The plugin maintains a cached copy of the watermarked image, which can be cleared and regenerated at any time!
The plugin uses PNG watermark images with transparency for precise control over the appearance of the watermarks. 
This plugin also supports simple text watermarks with adjustable color, size and transparency. 
The user friendly settings page allows for control over the appearance of your watermark. 
The watermark preview feature allows for easy testing of the plugin settings. 
The watermark size is controlled as a percentage of the target image, 50% means the watermark will be half the width of the target image.
This plugin needs to add to your .htaccess file, and will not work if you do not have a .htaccess file or mod_rewrite.
NOTE: 
This plugin may have a slight impact on the performance of your web server, use of the Included Basic Caching System is Highly Recommended! 
The premium version of this plugin also includes an Advanced Cache System which performs nearly identical to when the plugin is disabled.
<a href="http://MyWebsiteAdvisor.com/tools/wordpress-plugins/simple-watermark/" rel="nofollow ugc">Upgrade to Simple Watermark Ultra</a> for advanced 
watermark features including:
<ul>
<li>Improved Performance with Advanced Cache</li>
<li>Fully Adjustable Image Watermark Position</li>
<li>Fully Adjustable Text Watermark Position</li>
<li>Adjustable JPEG Image Output Quality</li>
<li>Highest Quality Watermarks using Image Re-sampling rather than Re-sizing</li>
<li>Lifetime Priority Support and Update License</li>
</ul>
Developer Website: http://MyWebsiteAdvisor.com/
Plugin Support: http://MyWebsiteAdvisor.com/support/
Plugin Page: http://MyWebsiteAdvisor.com/tools/wordpress-plugins/simple-watermark/
Requirements:
<ul>
<li>PHP v5.0+</li>
<li>WordPress v3.3+</li>
<li>GD extension for PHP</li>
<li>FreeType extension for PHP</li>
<li>.htaccess file and mod_rewrite</li>
</ul>
To-do:

Simple Watermark

Automatically watermark images as they are viewed

nxtweb

Next Watermark is the simplest way to add automatically text or/and image watermarks on your .gif, .jpg, .png and .webp photos when uploading them in the WordPress media library. 
You can choose the text, size, font, transparency, position and orientation of your watermark text. 
You can also use directly any watermak image in GIF, JPEG or PNG formats, choosing special effects, opacity, orientation and absolute, relative or preset positions. 
Watermarks can be applied on GIF, JPEG, PNG or WEBP images. 
You can choose the image types, the images sizes and the post types to apply your watermarks or not. 
You can use backup to save your images before watermarking, and restore them automatically with a simple button. 
English & French language available. It is very light too. 
The plugin uses PHP GD script Library.
This plugin comes with the following fonts, but you can add your own fonts. 
Arial, Arial Black, Comic Sans MS, Courier New, Impact, Tahoma, Times New Roman, Verdana
<h3>Languages</h3>
This plugin is available in English & French.
<h3>Donations</h3>
Keep this plugin alive and improving, your help is appreciated. 
<a href="https://www.paypal.com/donate/?hosted_button_id=DRNEFMLP7CU5Q" rel="nofollow ugc">Consider donating</a>!
<h3>Custom development</h3>
You need a new plugin? We can talk and help you with the plugin custom. 
At Next Web, we can develop your future new website or plugins adapted to your needs. 
Just contact <a href="https://nxt-web.com/" rel="nofollow ugc">Next Web</a>!

Next Watermark

Next Watermark helps you easily add automatically text or/and image watermarks on your images (GIF, JPEG, PNG and WEBP formats supported)! Backup/rest …

Simple Watermark vs Next Watermark