When saving, Photoshop strips metadata from files critical to a workflow

Question

Apple uses some extended attributes in their Spotlight indexed file metadata. When you open a file, make a change, and save it the metadata is gone.
As an example, an image from the web will have an extended attribute of kMDITemWhereFroms identifying the source URL. It also refers to email messages a file may have come from.
This is VERY useful information but the saving process destroys it!! This is critical to my workflow that this information (along with other extended attributes) be maintained! Can someone shed some light on this? If not, can anyone direct me to someone who can??
Thanks.
* Note: The same problem exists with Illustrator (CS3/CS4)

Answer 1

Jim - of course the original is not retained: the apps are doing a safe save (where you save to a new filename, then replace the original with the duplicate in a semi-atomic way). This is done using standard OS APIs whenever possible, and is done in most applications. All file saves in Photoshop behave the same way, except maybe PDF (which is in some code we don't control) and SaveForWeb (also different code).
Again, the root cause is an Apple bug in the way they chose to associate metadata with the files, and how they updated existing APIs to deal with the additional metadata. We might be able to work around this using new APIs -- but should apps have to change their code every time someone decides to add new metadata invisible to the app and separate from the file? Shouldn't the design of the metadata system be more robust, and work with existing applications? Shouldn't someone have thought about this before releasing a metadata system, that, well, nobody knew about?