One Hour Photo (2002)

Sy "the photo guy" Parrish has lovingly developed photos for the Yorkin family since their son was a baby. But as the Yorkins' lives become fuller, Sy's only seems lonelier, until he eventually believes he's part of their family. When "Uncle" Sy's picture-perfect fantasy collides with an ugly dose of reality, what happens next "has the spine-tingling elements of the best psychological thrillers!"