why is mila kunis pictured in how i met your mother season 1 case?

behind the dvd's in the season 1 is a picture that i think is from
forgetting sarah marshall, anyone know if/why that is?
yeah Jason Seigel is in that movie too, but she does not appear in
HIMYM at all, so i'm confused at why a picture of the 2 of them is in
the HIMYM season 1 box.