Common code for working with images in ROS:

camera_calibration_parsers contains routines for reading and writing camera
calibration parameters.

camera_info_manager provides a C++ interface for camera calibration information.
It provides CameraInfo, and handles SetCameraInfo service requests, saving and
restoring the camera calibration data.

image_transport should always be used to subscribe to and publish images. It
provides transparent support for transporting images in low-bandwidth
compressed formats. Examples (provided by separate plugin packages) include
JPEG/PNG compression and Theora streaming video.

polled_camera contains a service and C++ helper classes for implementing a
polled camera driver node and requesting images from it. The package is
currently for internal use as the API is still under development.

WWW: http://www.ros.org/wiki/image_common