THBImage.NET - Displays an image and offers all ways to align and stretch the image. It supports GIF, JPEG, EXIF, PNG, TIFF, EMF, WMF, Icon. By THBComponentware. [Commercial] - http://www.thbcomponents.com/products/prthbimgnetov.html
TrueColorToPalette - Convert true color images to paletted images using Floyd-Steinberg dithering algorithm. - http://www.asppainter.com/aspnetpalette.html
SilkWebware Image Canvas - Deliver real-time dynamically generated images including charts, diagrams or any other graphical application. - http://www.silkwebware.net/products/details.aspx?id=3e4de215-9d1f-4773-8efe-5e7c2ba7dc93
Image Gallery.NET - Automatic image thumbnail creation, paging, template and design time support. Source code available. By Rebex.NET - http://www.rebex.net/ImageGallery/
ArtForms for .NET - Image controls that render customizable graphics in real-time. By Progressive Consulting Technologies, Inc. - http://artforms.progressivex.com/