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

GrandPlugins

The plugin offers watermarks templates for bulk watermarks and single editor for applying watermarks on single images.
<h3>Short Description</h3>
Add Text and Image watermarks to your pictures and images easily.
<h3>Features</h3>
<ul>
<li>Watermark images using text and image watermarks, control the watermark position, rotation and repetition.</li>
<li>Customize the text watermark’s font size, font family and color.</li>
<li>Create Watermarks Templates for bulk watermarking.</li>
<li>Apply watermarks templates on bulk images selected directly from the media library.</li>
<li>Preview and apply watermarks on single image.</li>
<li>add custom fonts for text watermarks.</li>
</ul>
<iframe loading="lazy" class="youtube-player" width="750" height="422" src="https://www.youtube.com/embed/W0VJE7WdirY?version=3&rel=1&showsearch=0&showinfo=1&iv_load_policy=1&fs=1&hl=en-US&autohide=2&wmode=transparent" allowfullscreen="true" style="border:0;" sandbox="allow-scripts allow-same-origin allow-popups allow-presentation allow-popups-to-escape-sandbox"></iframe>
[Pro Version]
👉 <a href="https://grandplugins.com/product/wp-images-watermark/" rel="nofollow ugc">Premium</a> | <a href="https://grandplugins.com/documentation/wp-watermark-images/" rel="nofollow ugc">Documentation</a> 👈
Pro version includes all free features plus:
<ul>
<li>
unlimited Watermarks Templates You can create unlimited watermarks templates.
</li>
<li>
Apply unlimited watermarks You can add unlimited watermarks in watermarks templates or single-image Watermarks Editor.
</li>
<li>
Auto Watermarks Customize watermarks templates to be applied automatically on uploaded images, You can filter the auto-apply based on the image dimension [ max|min width and height ], the image filename prefix and the image uploaded location which it can be media or posts.
</li>
<li>
Watermarks Apply Type Choose to overwrite the image or create a new watermarked image.
</li>
<li>
Watermarks Apply Sub-sizes Choose which sub-sizes to apply the watermarks on.
</li>
<li>
Backups You can choose to create backup from images before applying watermarks in case of overwriting. You can restore original images either from image single image page or bulk-restore.
</li>
<li>
Bulk images Select Select images in bulk mode based on image’s post parent. You can select posts directly or based on filters [ posts availability – posts date range – posts authors – posts terms – etc…]
</li>
<li>
Auto Resize watermarks for each different image in bulk and auto watermarking.
</li>
<li>
Select watermarks Corner Offset.
</li>
<li>
Dynamic Watermarks for WooCommerce and MasterStudy LMS.
</li>
</ul>

GrandPlugins Image Watermark

The plugin offers watermarks templates for bulk watermarks and single editor for applying watermarks on single images.

Simple Watermark vs GrandPlugins Image Watermark