François-Régis Ferry

URL To Featured Image allows you to use an image hosted anywhere on the internet as the featured image (post thumbnail) for any post, page, or custom post type.
Perfect for: 
– Using CDN-hosted images as thumbnails. 
– Saving server space by not uploading large images. 
– Dynamically updating featured images from an external source.
Key Features: 
– Simple URL field in the post editor. 
– Works with posts, pages, and custom post types. 
– No extra database tables. 
– Fully compatible with WordPress themes and loops. 
– Uses standard WordPress functions like <code>the_post_thumbnail()</code>. 
– Ability to save the target image in the media libary if needed
How it works: 
When displaying the post, the plugin replaces the default WordPress featured image with the one provided via the URL.
<h3>Custom Hooks</h3>
<h4>Filters</h4>
<ul>
<li>
<code>friss_utfi_post_type_exclusions</code> 
Filters the post types where the URL To Featured Image metabox should not appear. 
Parameters:
<ul>
<li>(array) $exclusions_list List of post types where the metabox is excluded. </li>
<li>(object) $post Current post. 
Return: (array) Modified exclusions list.</li>
</ul>
</li>
<li>
<code>friss_utfi_url_allowed</code> 
Filters whether an external image URL is allowed before fetching. 
Parameters:
<ul>
<li>(bool) $authorization Whether the URL is allowed. </li>
<li>(string) $url The external image URL. </li>
<li>(array) $parts Parsed URL parts (from <code>wp_parse_url</code>). 
Return: (bool) True to allow, false to block.</li>
</ul>
</li>
<li>
<code>friss_utfi_allowed_mime_types</code> 
Filters the allowed MIME types for external images. 
Parameters:
<ul>
<li>(array) $mime_types Allowed MIME types. 
Return: (array) Modified list of MIME types.</li>
</ul>
</li>
<li>
<code>friss_utfi_max_image_size</code> 
Filters the maximum allowed image size when fetching external images. 
Parameters:
<ul>
<li>(int) $size Max file size in bytes. 
Return: (int) Modified maximum size.</li>
</ul>
</li>
<li>
<code>friss_utfi_image_data</code> 
Filters the raw image data fetched from the external URL. 
Parameters:
<ul>
<li>(string) $image_data Raw image data (string). </li>
<li>(object) $post Current post object. 
Return: (string) Modified image data.</li>
</ul>
</li>
<li>
<code>friss_utfi_external_featured_image_alt</code> 
Filters the alt text for the external featured image. 
Parameters:
<ul>
<li>(string) $alt_text The alt text (default: post title). </li>
<li>(int) $post_id Current post ID. 
Return: (string) Modified alt text.</li>
</ul>
</li>
<li>
<code>friss_utfi_post_thumbnail_html_preserve_existing_markup</code> 
Controls whether the existing markup is preserved before regenerating the HTML via the post_thumbnail_html filter hook. 
Parameters:
<ul>
<li>(bool) $preserve_existing_markup Whether to preserve or not the existing image tag markup. </li>
<li>(int) $post_id Current post ID. 
Return: (bool) True to preserve, false to skip this step.</li>
</ul>
</li>
<li>
<code>friss_utfi_post_thumbnail_html_attributes</code> 
Filters the image tag attributes for the recreated html content generated by the post_thumbnail_html filter hook. 
Parameters:
<ul>
<li>(array) $attributes The attributes array to filter. </li>
<li>(int) $post_id Current post ID. 
Return: (array) Modified attributes array.</li>
</ul>
</li>
<li>
<code>friss_utfi_allowed_img_attributes</code> 
Filters the whitelist of allowed attributes kept on the generated tag when rendering the external featured image. 
Parameters:
<ul>
<li>(array) $allowed_attributes List of allowed attribute names (default: src, alt, width, height, class, loading, decoding).</li>
<li>(int) $post_id Current post ID. 
Return: (array) Modified list of attribute names.</li>
</ul>
</li>
<li>
<code>friss_utfi_external_featured_image_styles</code> 
Filters the inline CSS styles applied to the external featured image. 
By default, the plugin enforces responsive behavior (<code>max-width:100%; height:auto;</code>). 
Parameters:
<ul>
<li>(string) $default_styles The default style string. </li>
<li>(int) $post_id Current post ID. 
Return: (string) Modified CSS styles.</li>
</ul>
</li>
<li>
<code>friss_utfi_active_post_types</code> 
Filters the final list of active post types for which the URL To Featured Image feature is enabled. 
Parameters:
<ul>
<li>(array) $active_post_types Current list of active post type slugs. 
Return: (array) Modified list.</li>
</ul>
</li>
<li>
<code>friss_utfi_active_post_types_posttype_exclusions</code> 
Filters the list of post types excluded before computing active post types. 
Parameters:
<ul>
<li>(array) $exclusions Current exclusions (internal post types or ones you want suppressed). 
Return: (array) Modified exclusions list.</li>
</ul>
</li>
</ul>

URL To Featured Image

Set any external image URL as your post's featured image automatically.

Impossible Dreams Network

Yakov Shafranovich

Adds basic support for external products to WooCommerce 
variations/variable products. This plugin allows you to define an external 
URL on any variation and will then open that link when the user 
clicks on the Add To Cart button. Because the Javascript is used for this, 
any adding to cart that is done via the backend such as with APIs will not 
redirect properly.
Note that as of 03/2023 this plugin is not longer under active development.
<h4>Shortcode support</h4>
This plugin provides two shortcodes that you can use within your site: 
1. [wcev_product_attr] – allows you to display an product attribute, use the “name” attribute to find the right attribute. 
2. [wcev_var_field] – allows you to display a custom field, attribute or data element for a variation, use the “id” attribute to point to the right field. 
The order of precendence is as follows: custom fields, attributes, then data elements. 
3. [wcev_var_postdate] – displays the formatted post date and time for a variation, doesn’t take attributes.
<h4>External SKU and status fields</h4>
In addition to the external URL field, a second field called “External SKU” is provided for each variation. 
You can set this field and then use the provided shortcode to display it. 
The purpose is to track the external SKU separately from the internal one.
There is now ability to specify the ‘Add to Button’ text in a specific variation. If the global setting is set, the variation-specific field will override it.
<h4>Settings</h4>
To change settings, go to WooCommerce Settings -> Products -> External Variations. The following are available: 
* Ability to change if links open in new or same window 
* Ability to change if links open when the ‘Add to Cart’ button is clicked or when the variation is selected 
* Ability to override the ‘Add to Cart’ button text for all external variations
<h4>More Details</h4>
Please note that this plugin has only been tested in a vanilla WordPress / WooCommerce 
installation without any other plugins. If you have other plugins that modify 
the functionality of the Add to Cart button, this plugin may not work or 
cause unintended consequences.
Source code for this plugin can be found at <a href="https://github.com/impossibledreams/wc-external-variations" rel="nofollow ugc">Github</a>
You can find this plugin at <a href="https://wordpress.org/plugins/wc-external-variations/" rel="ugc">WordPress.org</a>
<h3>Known Issues</h3>
When the number of variations exceeds 30, the plugin stops working. This is due 
to a WooCommerce limit and can be bypassed by using a filter as described here: 
https://docs.woocommerce.com/document/change-limit-on-number-of-variations-for-dynamic-variable-product-dropdowns/

WC External Variations

A WordPress plugin that adds basic support for external products to WooCommerce variations/variable products. No longer under active development as of …

URL To Featured Image vs WC External Variations