RPhoto is a handy image editor to simplify cropping of digital camera pictures and avoid white borders introduced by incorrect height/width ratios. It also has lossless rotate and flip features, as well as a unique way to rectify a bad angle by only drawing a horizontal or vertical line.
Bibble is a professional image-manipulation application for processing of raw photos from digital cameras. It provides a fast and high quality raw workflow. It features a fully integrated browser, user configurable tools/views, powerful batch processing, raw optimized printing, a flexible renaming system, advanced settings for copy and paste, IPTC meta-data support, and tethered shooting.
ExifTool is a platform-independent Perl library plus a command line application for reading, writing, and editing meta-information in image, audio, and video files. It supports many different types of metadata including EXIF, GPS, IPTC, XMP, JFIF, GeoTIFF, ICC Profile, Photoshop IRB, FlashPix, AFCP, and ID3, as well as the maker notes of many digital cameras.
Optar is a software codec that generates 2D bar codes for data storage on paper using a black and white laser printer and scanner. It fits 200kB on an A4 page, uses Golay forward error correction codes to ensure reliability, and can also be used to store data on photographic film.
VideoDog is a command line tool to grab frames from a Video4linux-compliant device. It can export a file in raw, PNM, or JPG formats. It can also do loop capture using multiple buffers, or just be used to set/retrieve device data or scripts. It presents a programming interface for implementing image transformations and effects. There are some examples in the source code. No external libraries are required.