Converseen is an image converter and resizer written in C++ with the powerful Qt4 libraries. Thanks to the Magick++ image libraries, it supports more than 100 image formats like DPX, EXR, GIF, JPEG, JPEG-2000, PhotoCD, PNG, Postscript, SVG, TIFF, and many others. Converseen allows you to convert, resize, rotate, and automatically flip an unlimited number of images. It can save you time because it can process more than one image with one mouse click. It features a very simple user interface without strange options.
Thumbnailator is a thumbnail generation library with a fluent interface for Java. It simplifies the process of producing thumbnails from existing image files and image objects by providing an API which allows for fine tuning of thumbnail generation, while keeping the amount of code that needs to be written to a minimum.
AstroStack is an easy-to-use astronomical imaging and processing tool geared towards the use of inexpensive webcam CCDs. It provides a very tunable environment to produce the best quality images. It supports the following features: tunable webcam sampling; image stacking (averaging, additive etc.); pre and post-capture gamma (brightness) and contrast correction; dark-shot CCD calibration (subtractive); and an internal 16-bit grey-scale format for optimal resolution.