digiKam is an advanced digital photo management application for Linux, Windows, and Mac-OSX. With the Kipi-Plugins it can also manipulate image files in almost any way that users can.
Features include Rotate, crop, vertical/horizontal flip, lossless JPEG operations (90° steps), color management, 16bit color depth, Light Table, Exif, IPTC, XMP, GPS metadata, adjust colors/brightness/levels, elaborate Black and White conversion, automatic lens correction, anti-vignetting, sharpening tools, vibrance, many filters, Batch operations, export to archive, HTML, flickr, gallery2, picasaweb, smugmug, iPod, facebook, 23hq, flash, Fit to window, zoom, pan, Light Table, Slideshow+Effects, OpenGL viewer, Face detection and tagging support, XMP sidecar support, Reverse geocoding, Image versioning, Pick Labels & Color Labels support to improve photographic Work-flow, many RAW decoding features,...
License is GNU GPL
Would be great to see it on portableapps.com! I guess porting is not that hard, since it is open source software.
Software is available at
http://www.digikam.org/
Closed for Commenting, see continuation here - mod GC: https://portableapps.com/node/59489