album is a free HTML/XHTML photo album and gallery generator that supports themes/skins. You can choose different themes or write your own to get different layouts and styles. It creates all your thumbnails (including directory thumbnails) and descends into directories so you can organize your photos. See the home page for more examples. album is also multi-lingual, with many languages being added all the time. N.B.: The purchase link is provided for donations; the software does not cost anything.
Jhead is a command line driven utility for extracting digital camera settings from the Exif format files used by many digital cameras. It handles the various confusing ways these can be expressed, and displays them as F-stop, shutter speed, etc. It is also able to reduce the size of digital camera JPEGs without loss of information, by deleting integral thumbnails that digital cameras put into the Exif header. If you need to add Exif support to a program, this is a simple program to cut and paste from. Many projects, including PHP, have reused code from this utility.
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.
UFRaw is a utility for converting and manipulating raw images from digital cameras. It can be used as a stand-alone tool or as a Gimp plugin, and images can be batch processed using the commandline interface. UFRaw reads most existing raw formats using Dave Coffin's raw conversion utility DCRaw, and it supports basic color management using Little CMS, allowing the user to apply color profiles. For Nikon users, UFRaw has the advantage that it can read the camera's tone curves. Even if you don't own a Nikon, you can still apply a Nikon curve to your images.
Xpdf is a viewer for Portable Document Format (PDF) files. (These are also sometimes also called 'Acrobat' files, from the name of Adobe's PDF software.) The Xpdf project also includes a PDF text extractor, PDF-to-PostScript converter, and various other utilities. It runs under the X Window System on UNIX, VMS, and OS/2. The non-X components (pdftops, pdftotext, etc.) also run on Win32 systems, and should run on pretty much any system with a decent C++ compiler. Xpdf is designed to be small and efficient. It can use Type 1 and TrueType fonts.
Potrace is a utility for tracing a bitmap (that is, transforming a bitmap into a smooth, scalable image). The input is a portable bitmap (PBM), and the default output is an encapsulated PostScript file (EPS). A typical use is to create EPS files from scanned data, such as company or university logos, handwritten notes, etc. The resulting image is not "jaggy" like a bitmap, but smooth. It can then be rendered at any resolution.
QCad is a powerful but easy to use 2D CAD program for Linux, Windows, and Mac OS X. It uses DXF as its standard file format. While other CAD packages are often rather complicated to use, QCad tries to stay comfortable, and even an absolute beginner can create professional drawings with a minimum of effort.
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.
BINS is a valid HTML 4 photo album generator with support for internationalization, EXIF, and customizable charset encoding, including UTF-8 (Unicode). Albums can contains other sub-albums. The appearance of the album can be fully personalized by using template and configuration parameters. The number and size of scaled pictures can be chosen in pixels or percentage of the original image. Several description fields (date, location, etc.) can be associated with the pictures, and you can add additional description fields. A command line utility or a GTK+ GUI can be used to set or edit description fields. BINS can use the EXIF data structure found in some pictures to automatically fill some fields (most notably, date and time) and to produce a page providing all information available on the picture, as well as the DigiCam settings when the photo was taken. All image meta-data are stored in XML files.