Here is a list of some common Open Source imaging software for Linux. Click on the name to go to their official homepage for more information. I haven't divided the list in purpose categories, because some programs have multiple functions.
KPhotoAlbum (previously known as KimDaBa) is an image viewer and organizer for Unix-like systems created and maintained by Jesper K. Pedersen. The core philosophy behind its creation was that it should be easy for users to annotate images and videos taken with a digital camera. Users can search for images based on those annotations (also called categories) and use the results in a variety of ways. Features include slideshows, annotation, KIPI plugin support for manipulating images, and Boolean searches.
KPhotoAlbum is licensed under the GNU General Public License version 2. Although it is free, users are encouraged to donate money to help the development of the application.
LightZone is professional-level digital darkroom software for Windows, Mac OS X, and Linux, that includes RAW processing and editing. Rather than using layers in the way that other photo editors do, LightZone lets the user build up a stack of tools which can be rearranged, readjusted, turned off and on, and removed from the stack. It's a completely non-destructive editor, where any of the tools can be re-adjusted or modified later — even in a different editing session. A tool stack can even be copied to a batch of photos at one time. LightZone always operates in a 16-bit linear color space with the wide gamut of ProPhoto RGB.
Rapid Photo Downloader for Linux is written by a photographer for professional and amateur photographers. Its goal is to be the best photo and video downloader for the Linux Desktop. It is free software, released under the GNU GPL license.
Phatch is an user friendly, cross-platform Photo Batch Processor and Exif Renamer with a nice graphical user interface. Phatch handles all popular image formats and can duplicate (sub)folder hierarchies. Phatch can batch resize, rotate, apply shadows, perspective, rounded corners, … and do much more actions in minutes instead of hours or days if you do it manually.
darktable is an open source photography workflow application and RAW developer. A virtual lighttable and darkroom for photographers. It manages your digital negatives in a database, lets you view them through a zoomable lighttable and enables you to develop raw images and enhance them.
Open Source Photo manager for KDE desktop . It also works on a GNOME desktop. However, it's intended for a KDE desktop environment.
Open Source Raw converter is GTK based.
An Open Source Raw converter. This software can be used as a stand alone converter as well as a plugin for the GIMP and Cinepaint. It uses the DCRaw library. Check out my review for more information.
An Open Source Paint program.
Probably the best Open Source image manipulation program available. It runs on Linux, Mac and Windows.
The GIMP as a one-screen program (like Photoshop).
Open Source image editor for KDE desktops. Krita is part of Koffice.
Open Source program for creating webalbums. Very easy to use. Check out my review on AlbumShaper.
Open Source Photo Management. Check out my review on f-spot.
Fotoxx is a free open source Linux program for photo editing and collection management.
GTK Photo Gallery is an album to manage small and medium-sized photograph collections. It allows quick management by processing multiple files together
GTKRawGallery is a workflow oriented photo retouching software for camera raw image development.
Open-source and cross-platform (UNIX, Mac OS X and Windows) picture manager / organizer written in Perl/Tk.
Mapivi is a photo management tool with focus on JPEG pictures.
Open Source Color management program for creating color profiles.
An Open Source image browser that features single click access to view images and move around the directory tree. Check out my review on GQview.
Geeqie is a lightweight Gtk+ based image viewer for Unix like operating systems. Check out my review on Geeqie.
gThumb is an image viewer and browser for the GNOME Desktop. With gThumb you can easily view, manipulate and manage your photo’s. Check out my review on gThumb.
Open Source panorama stitching application. Check out my review on hugin.
An Open Source, QT based application for HDR image creation.
Also known as QtpfsGUI. See above.
ArgyllCMS is an ICC compatible color management system.
gPhoto2 is a free, redistributable, ready to use set of digital camera software applications for Unix-like systems, written by a whole team of dedicated volunteers around the world. It supports more than 1300 cameras
gPhoto2 runs on a large range of UNIX-like operating system, including Linux, FreeBSD, NetBSD, MacOS X, etc. gPhoto is provided by major Linux distributions like Debian GNU/Linux, Ubuntu, Gentoo, Fedora, openSUSE, Mandriva, etc.
ImageMagick is a software suite to create, edit, and compose bitmap images. It can read, convert and write images in a variety of formats (over 100) including DPX, EXR, GIF, JPEG, JPEG-2000, PDF, PhotoCD, PNG, Postscript, SVG, and TIFF. Use ImageMagick to translate, flip, mirror, rotate, scale, shear and transform images, adjust image colors, apply various special effects, or draw text, lines, polygons, ellipses and Bézier curves.
BorderMaker is a (Dutch) Freeware tool to add borders, text and water brands in digital photo’s. Check out my review on Bordermaker.
GPSCorrelate is an easy to use GTK based program which can correlate GPS data from your GPS device and put the GPS coordinates in the EXIF metadata of your pictures according to the timestamp.