Huh? Since when is that a picture of Shim Eunji? I think you might be mixing up the picture of J-min with Shim Eun ji when they collaborated on a song.
Shim Eunji / Sim Eun Jee looks like this:
She's like the second or third most senior songwriter at JYP Publishing. Debuted with a song for f(x) in 2009, and then wrote for pretty much everyone over the years.
For Formula of Love, she only served as a full songwriter (lyrics and music composition) for Last Waltz. She was lyricist only for Scientist and 1,3,2. The actual composers of 1,3,2 were Marcus Van Wattum, Jenson Vaughan, Lauren Dyson, and Alexander Pavelich.