NsThemes

Apply your watermark on your WooCommerce product images — without overwriting them!
NS Watermark For WooCommerce overlays a watermark image on top of your shop and single-product photos at display time. 
The original files stored in your Media Library are never modified.
Features (free version)
<ul>
<li>Choose any image from your Media Library as the watermark.</li>
<li>Always show the watermark, or show it only to guests (not logged-in users).</li>
<li>Enable / disable with a single setting.</li>
<li>Compatible with WordPress 7.0 and WooCommerce 10.8.1.</li>
<li>No GD extensions need to be installed separately (bundled with PHP ≥ 7.4).</li>
</ul>
3rd Party / External Services
<ul>
<li>PluginEye — used for opt-in usage tracking (plugin activation/deactivation events, site address, WordPress version, active plugin list). Data is collected only after explicit user consent is given on the opt-in screen shown at first activation. Read more: <a href="https://www.plugineye.com/privacy-policy/" rel="nofollow ugc">Privacy Policy</a> — <a href="https://www.plugineye.com/terms-of-service/" rel="nofollow ugc">Terms of Service</a>. This service is provided by NsThemes.</li>
</ul>
All watermark image processing is performed locally on your web server using PHP’s built-in GD library. No image data is sent to external servers.

NS Watermark For WooCommerce

Protect your WooCommerce product images by overlaying a watermark on-the-fly — no permanent changes to your files.

babaksafayi

Image Bridge is a Light weight WordPress plugin that allows you to add custom image URLs, alt and title attributes to the featured images of your pages and posts and products.
<h3>Usage</h3>
<ol>
<li>Go to the post or page editor in WordPress.</li>
<li>In the meta box titled ‘Image Bridge’, enter the custom image URL, alt and title attributes for the featured image.</li>
<li>Save or update the post or page.</li>
<li>The featured image will now display the custom image with the specified alt and title attributes.</li>
</ol>

Image-Bridge

Image Bridge is a Light weight WordPress plugin that allows you to add custom image URLs, alt and title attributes to the featured images of your page …

NS Watermark For WooCommerce vs Image-Bridge