The following pictures feature Hayden and Harper wearing the exact same shirt.
Hayden's pictures are from May 2008 (when he was about 15-months-old). Harper's pictures are from February 2012 (she is about 9-month-old).
The first two sets feature four pictures that are relatively comparable in composition. The following pictures are just adorable pictures of the two of them (still wearing that same shirt from those same respective time periods).
And here are the pictures that aren't as directly comparable - yet they are just as adorable.