Regenerate Thumbnails
Regenerate Thumbnails allows you to regenerate the thumbnails for all of your image attachments. This is very handy if you’ve changed any of your thumbnail dimensions (via Settings -> Media) after previously uploading images.

FEATURED CONTENT GALLERY
http://wordpress.org/extend/plugins/featured-content-gallery/
Featured Content Gallery creates an automated, fully customizable rotating image gallery anywhere within your WordPress site. Choose your images and display categories, pages or posts with custom overlay text and a thumbnail carousel. Custom options include gallery size, color, style and more.

LIGHTBOX PLUS
http://wordpress.org/extend/plugins/lightbox-plus/
Lightbox Plus implements ColorBox as a lightbox image overlay tool for WordPress. ColorBox was created by Jack Moore and is licensed under the MIT License. Lightbox Plus permits users to view larger versions of images without having to leave the current page. Lightbox is able able to lightbox WordPress galery images, display simple slide shows, along with video and content in overlays. The use of the dark or light background, which dims the page over which the image has been overlaid, also serves to highlight the image being viewed. Lightbox Plus captures the image title for display in the overlay.

NEXTGEN GALLERY
http://wordpress.org/extend/plugins/nextgen-gallery/
NextGEN Gallery is a full integrated Image Gallery plugin for WordPress with a Flash slideshow option. Before I start writing the plugin I study all photo and picture plugins for WordPress, I figure out that some of them are really good and well designed, but I missed a simple and easy administration back end to handle multiple photos, galleries and albums.

LAZYEST GALLERY
http://wordpress.org/extend/plugins/lazyest-gallery/
Lazyest Gallery is an integrated image gallery with automatic thumb and slide creation.

DYNAMIC HEADERS
http://wordpress.org/extend/plugins/dynamic-headers/
Dynamic headers fills a void that has been present for a while in WordPress. It is a small, easy to use plugin that allows you to manage what header media is shown on each page/post. Unlike some other plugins however, this plugin allows you to use any image file OR a .swf Flash file. So you are no longer limited to a certain media type for your headers and you are no longer limited to one site-wide header.

KIMILI FLASH EMBED
http://wordpress.org/extend/plugins/kimili-flash-embed/
Kimili Flash Embed is a plugin for WordPress that allows you to easily place Flash movies on your site. Built upon SWFObject javascript code, it is standards compliant, search engine friendly, highly flexible and full featured, as well as easy to use.