My camera's batteries run out and the stored date was wrong and the I have now about 100 photos with an incorrect date. Is there any app that can change the photos date? Something that can calculate NewDate=(OldDate - 1day.2months.12hours), so I don't have to calculate the difference and enter the date for every file?
exiv2 should be the easiest solution to do this:
Excerpt from the man page:
Also, I'd suggest you try this first on a copy of the photos, not on the originals.