"Open With"->"Change All" corrupts your file (Resource forks, extended attributes, creation date)

I finally know why some of my files get corrupted.

If you use the following method to assign one kind of file to always open with the same application;

http://docs.info.apple.com/article.html?path=Mac/10.6/en/8387.html

(File -> Get Info -> Open With -> Change All)

an extended attribute will be added to your file.

You can examine that by typing "ls -l" in Terminal. If you see an @-sign after permissions than you have an extended attribute in that file.

To see what it contains, type "xattr -l filname.jpg" in Terminal.

Besides that is adds an extended attribute (which can be deleted with the "xattr --help" command) the modification date of the selected file will be changed.

I think this is irritating because I wan't to keep my master photos with the same modification date as creation date.

What else does it effect besides the modification date and to add extended attributes? Does my metadata get intact?

(If you further want to make a backup copy on for example a FAT32 filesystem than your got a new problem. FAT32 doesn't support resource forks, so besides filename.jpg you will have an additional ._filename.jpg of 4kb)