ChrisHurst

MyWebsiteAdvisor

This plugin allows you to watermark your previously uploaded images using a PNG image file with transparency as well as text signature. 
The user friendly settings page allows for control over the appearance of your watermark. 
You can set your watermarks to always be a specific percentage of the target image. 
This plugin will add the watermarks to ALL of the images in your WordPress uploads directory.
Please BACK UP all of your uploads via FTP before using this plugin!
<a href="http://mywebsiteadvisor.com/plugins/bulk-watermark/" rel="nofollow ugc">Upgrade to Bulk Watermark Ultra</a> for advanced 
watermark features including:
<ul>
<li>Fully Adjustable Text and Image Watermark Positions</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>
Check out the <a href="http://www.youtube.com/watch?v=XkFXBjfzw2I&hd=1" rel="nofollow ugc">Bulk Watermark Plugin for WordPress Video Tutorial</a>:
<iframe loading="lazy" class="youtube-player" width="750" height="422" src="https://www.youtube.com/embed/XkFXBjfzw2I?version=3&rel=1&showsearch=0&showinfo=1&iv_load_policy=1&fs=1&hl=en-US&autohide=2&hd=1&wmode=transparent" allowfullscreen="true" style="border:0;" sandbox="allow-scripts allow-same-origin allow-popups allow-presentation allow-popups-to-escape-sandbox"></iframe>
Developer Website: http://MyWebsiteAdvisor.com/
Plugin Support: http://MyWebsiteAdvisor.com/support/
Plugin Page: http://mywebsiteadvisor.com/plugins/bulk-watermark/
Compare Watermark Plugins: http://MyWebsiteAdvisor.com/tools/wordpress-plugins/watermark-plugins-for-wordpress/
Video Tutorial: http://mywebsiteadvisor.com/learning/video-tutorials/bulk-watermark-tutorial/
Requirements:
<ul>
<li>PHP v5.0+</li>
<li>WordPress v3.3+</li>
<li>GD extension for PHP</li>
<li>FreeType extension for PHP</li>
</ul>
To-do:

Bulk Watermark

Adds an image and/or text watermark to all uploaded images, using PNG images with transparency.

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.

Bulk Watermark vs GrandPlugins Image Watermark