Satish Gandham

By default WordPress generates images of all intermediate sizes registered by themes/plugins for every image uploaded, flooding your uploads folder with images you will never be using. 
In most cases you need the images of all dimensions only for the one set as featured image. 
This plugin prevents WordPress from generating thumbnails registered by themes and plugins, and generates them dynamically when required.
<h3>Another important use of this plugin, the main reason why its developed is</h3>
Different themes use different thumbnail sizes. When you switch to a new theme, 
WordPress just gives the image whose size closely matches the size of the thumbnail being called without generating an image with the required dimensions. 
In most cases the best match is the full size image, which adds lot of weight to your page and also makes it look awful. 
There are plugins to rebuild thumbnails, but they do it for every image uploaded and again flooding your uploads folder. 
Also these plugins timeout on a shared server if you have lot of images.
*This only works with sizes registered by add_image_size() function.

Dynamic Thumbnails

If thumbnails are correctly generated, the plugin breaks the rendering of all my archive pages. Too bad.

Breaks archive pages

A simple plugin for theme developers to dynamically generate thumbnails on the fly without having to ask the users to manually regenerate them.

Christian Foellmann

Ankit Pokhrel

Dynamically adds multiple featured image or multiple post thumbnail functionality to your page, posts and custom post types. This plugin provides you an interface to add any number of featured image as you want without writing a single line of code. These featured images can then be collected by the various theme functions.
Overview
Dynamic Featured Image enables the option to have MULTIPLE featured images within a post or page. 
This is especially helpful when you use other plugins, post thumbnails or sliders that use featured images. 
Why limit yourself to only one featured image if you can do some awesome stuffs with multiple featured image? 
DFI allows you to add different number of featured images to each post and page that can be collected by the various theme functions.
<blockquote>
A NOTE ABOUT SUPPORT: We’re here to help troubleshoot bugs, but please don’t set expectations early as the support forums at WordPress.org are only checked once in a while.
</blockquote>
How it works? 
1. After successfull plugin activation go to <code>add</code> or <code>edit</code> page of posts or pages and you will notice a box for second featured image. 
2. Click <code>Set featured image</code>, select required image from “Dynamic Featured Image – Media Selector” popup and click <code>Set Featured Image</code>. 
3. Click on <code>Add New</code> to add new featured image or use <code>Remove</code> link to remove the featured image box. 
4. You can then get the images by calling the function <code>$dynamic_featured_image->get_featured_images([$postId (optional)])</code> in your theme. (<a href="https://github.com/ankitpokhrel/Dynamic-Featured-Image/wiki" title="Documentation for current version" rel="nofollow ugc">Click here for details</a>) 
5. The data will be returned in the following format.
<pre><code>array
 0 => 
 array
 'thumb' => string 'http://your_site/upload_path/yourSelectedImage.jpg' (length=50)
 'full' => string 'http://your_site/upload_path/yourSelectedImage_fullSize.jpg' (length=69)
 'attachment_id' => string '197' (length=3)
 1 => 
 array
 'thumb' => string 'http://your_site/upload_path/yourSelectedImage.jpg' (length=50)
 'full' => string 'http://your_site/upload_path/yourSelectedImage_fullSize.jpg' (length=69)
 'attachment_id' => string '198' (length=3)
 2 => ...
</code></pre>
Resources 
1. <a href="https://github.com/ankitpokhrel/Dynamic-Featured-Image/wiki" title="Documentation for current ver." rel="nofollow ugc">Detail Documentation</a>. 
2. <a href="https://stackoverflow.com/questions/tagged/dynamic-featured-image" title="StackOverflow Tag" rel="nofollow ugc">StackOverflow Tag</a>.
MultiSite Info 
You can use <code>Network Activate</code> to activate plugin for all sites on a single install. It is only available on the Network admin site not anywhere else. 
Simple <code>Activate</code> activates for the site you are currently on. These will be permitted to be activated or deactivated on ANY blog.
While deleting the plugin from the <code>Network</code> be sure that the plugin is deactive in all installation of your WordPress network.
Contribute 
If you’d like to check out the code and contribute, join us on <a href="https://github.com/ankitpokhrel/Dynamic-Featured-Image" title="View this plugin in github" rel="nofollow ugc">Github</a>. 
Pull requests, issues, and plugin recommendations are more than welcome!

Dynamic Featured Image

Works fine!

Dynamically adds multiple featured image (post thumbnail) functionality to posts, pages and custom post types.

Dynamic Thumbnails vs Dynamic Featured Image