Creation Date and Modified Date Swapped

[Galton]

When I copy pictures from my camera to my hard disk the

Created Date Column shows The date I copied the files 04/01/08 12:18:49

Modified Date Column shows The Creation Date 12/10/07 16:57:42

If I open a file edit and save then the modified date is 04/01/08
thus loosing any record of the creation date.

I am doing something wrong? Or is something wrong with my system?

Thank You.