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" title="Bulk Watermark for WordPress Tutorial" width="750" height="422" src="https://www.youtube.com/embed/XkFXBjfzw2I?feature=oembed" frameborder="0" allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture; web-share" referrerpolicy="strict-origin-when-cross-origin" allowfullscreen></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.

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 …

Bulk Watermark vs Next Watermark