Headcanon: Pam chose matching outfits for her and Eric to wear for Russell’s “disposal”. Ginger took the photograph because Pam thought they looked cute.
Pam decided Eric’s hair needed more sassyness, so she made him slick it back but he wouldn’t let Ginger take another photo because they had more urgent matters to attend to.
Eric keeps the photo in his office because it reminds him of the night that Pam kicked ass and took out Reuben, it reminds him that he trained her well.
Pam & Eric: 6.01 “Who Are You, Really?”