Change just the year in a bunch of pictures?

Yes there are. The meta info format is called EXIF, and there is a command line tool called exiftool which can to exactly that.

Example invocations from the man page:

   exiftool -DateTimeOriginal-=’0:0:0 1:30:0’ dir
        Adjust original date/time of all images in directory "dir" by
        subtracting one hour and 30 minutes.  (This is equivalent to
        "-DateTimeOriginal-=1.5".  See Image::ExifTool::Shift.pl for
        details.)

   exiftool -createdate+=3 -modifydate+=3 a.jpg b.jpg
        Add 3 hours to the CreateDate and ModifyDate timestamps of two images.

   exiftool -AllDates+=1:30 -if ’$make eq "Canon"’ dir
        Shift the values of DateTimeOriginal, CreateDate and ModifyDate
        forward by 1 hour and 30 minutes for all Canon images in a directory.
        (The AllDates tag is provided as a shortcut for these
        three tags, allowing them to be accessed via a single tag.)

I am sure you can set the year to exactly 2010 in some way.