Jeff Stieler

Super Widgets let you display the Title, Featured Image, and Excerpt of a selected post or posts in your sidebar.
Narrow down posts to feature by blog (if multisite), post type, or taxonomy.
Show a single post (post/page/custom post type) with the Single Post (Post Type) widget.
Show the most recent post in a selected taxonomy with the Single Post (Taxonomy) widget.
Show the most recent X posts in a selected taxonomy with the Multi Post widget.

Super Widgets

Feature posts in your sidebar.  Select posts by Blog (multisite), individually, by Post Type, or by Tag/Category/Taxonomy.

Trân Minh-Quân

This plugin is destined to intermediate users.
It helps you find image that is attached to a post in this priority: – Custom field (name can be one of these: img, image, thumbnail) – Uploaded/Attached image
NOTE 
If you have allow_url_fopen you can get image from an URL Path for Custom Field to your uploaded files is: /year/month/image or /image (depends on your settings for upload directory)
Custom fields use these sets * (img, img_title, img_alt, img_class) -> CSS: img-[img_class] * (image, image_title, image_alt, image_class) -> CSS: image-[image_class] * (thumbnail, thumbnail_title, thumbnail_alt, thumbnail_class) -> CSS: thumbnail-[image_class] * The value of img_class or image_class or thumbnail_class is case non-sensitve (Ex: CSSClass will be cssclass) * case sensitive and non-permutable
Example
To be used best in the Loop caro_the_image($post->ID); shows the custom-size image. caro_get_the_image($post->ID); returns the custom-size image HTML code. caro_the_image_url($post->ID); shows the URL of the custom-size image. caro_get_the_image_url($post->ID); returns the URL of the custom-size image.

WPVN – Thumbnailer

This plugin helps you know how hooks are called and let you unload actions/filters (this is useful when you want to unload, not deactive, plugins base …

Super Widgets vs WPVN – Thumbnailer