This script manages several issues of JPEG image manipulation: EXIF header, icons, rotation, Colorsync. Its goal is to improve compatibility between OS X applications and other software, specifically from Canon.
The first goal is to insert back an EXIF header in an image from which it has been removed or modified by an image manipulation program. It is the case for all Quicktime applications under OS X (Image Capture, Preview, iPhoto). They modify coding of headers and suppress some proprietary fields (e.g. from Canon). Photos are thus deprived of some shooting informations. If transferred back in the camera or on a memory card they are sometimes unreadable.
This script also able to rotate the image in a lossless process. This is not the case with iPhoto. One can revert to the original of iPhoto and then rotate it with this script.
For a correct color rendering in OS X apps, itis necessary to include a Colorsync profile in the images. Otherwise they are too bland (for camera pictures). "Image Capture" can include a profile at download, but mess the exif header. It is better to do it latter with this script.
The Readme/Usage are in script comments, you can open it with standard Apple application "Script Editor".
This "Manual" is also on the web site.