Video Contact Sheet *NIX creates a contact sheet (preview) from videos by taking still captures distributed over the length of the video. The output image contains useful information on the video such as codecs, file size, screen size, frame rate, and length. It requires MPlayer or FFmpeg and ImageMagick. It is confirmed to work on Linux and FreeBSD, and possibly other POSIX/UNIX systems.
ColorPicker is a red-green-blue color picker with very good precision that integrates with any interface, allowing it to change on the fly. It is designed to work within a graphical component to allow the user a more accessible and flexible interface, and can be applied to regions or text. It is fully compatible with applets designed with the old JDK 1.1 and compatible with any Java Container. Each of red, green and blue are selected according to the full 256 color scale.
pngcrush is an excellent batch-mode compression utility for PNG images. Depending on the application that created the original PNGs, it can improve the file size anywhere from a few percent to 40% or more (completely losslessly). The utility also allows specified PNG chunks (e.g. text comments) to be inserted or deleted, and it can fix incorrect gamma info written by Photoshop 5.0 as well as the erroneous iCCP chunk written by Photoshop 5.5.
netpbm-free is Debian's fork of netpbm that was designed with security of code, reliability of interfaces, and freedom of software in mind. It is a suite of over 200 different programs from different authors, and is itself a fork of pbmplus. The suite supports almost every graphic format (including JPEG, PNG, BMP, ICO), and can create, change, crop, rotate, and transform in and between these formats.