Original title: date on file chanes

Whenever I open my pictures in Photo Gallery, whether or not I change anything or even look at the photo, the date stamp is changed, so when I want to only backup my changed photos, my backup software shows that all the files were changed, when I know for a fact that they were not changed. I do a frequent backup, and it takes time to backup 1000+ photos, when I only want to backup those that were changed.

For clarification, I am talking about the date-time stamp that is visible in Explorer, not the date the photo was taken.

Thanks,

BJ