This looks like a bug: Even if the 3 options "Keep original date for..." are unticked, using "Change Timestamp" the application manages to keep the original date unchanged. Doing the same with "Edit IPTC", the application let the O/S updating the File Modification Date, as expected.unticked: when the image metadata is written and the file modified date is automatically updated by the operating system, then the program actively overrides this by reinstating the previous value
People have different workflows:
- Some, like me, would like to keep the original date at least for some hours or days. This allows to keep a set of files if the right sequence up to the moment they can be renamed with a timestamp. This is necessary because some files don't have metadata or embedded date is unreliable or inaccessible (video files is an example but many graphic format as well). So my option is to let Xnview manage to keep original File Modification Date while I'm updating / changing these files.
- Your preference - Always let the OS updating the File Modification Date when the content of the file is changed is fully understandable. I would say it's made for purpose, tracking changes. It's fine for a workflow that would keep track of any change and store multiple copies, different modifications of an original.