I'm still in the process of tagging pages that were migrated from the old site, so for now you're best off using the search engine rather than relying on the tags.
- Change date of image EXIF data - Increment by 2 years: exiftool "-allDates+=2:0:0 0:0:0" [files] Decrement by 6 hours: exiftool "-allDates-=0:0:0 6:0:0" [files] [files] can be any list of filenames, with normal shell expansions (e.g. wildcards) allowed.