Could it be
Kidnapped by Her Lord and Master by greyangel? In this fic Buffy sleeps with Spike and doesn't really know him when she does. She ends up with twins. I don't remember there being a photo place involved, though.
Summary: All human - Present day – NC17 – Baby fic – Romance. Arrogant, aristocratic and ruthless businessman, Lord William Beauford, tricked naïve Elizabeth Summers into his bed and broke her heart. Eighteen months later William finds her again, but she's no longer the same girl who fell so eagerly into his arms. Yet, there's more than one surprise in store for William while he pursues a hostile and very reluctant Elizabeth. When she refuses to see things his way, William resorts to kidnapping to win his girl's heart.
Sorry if this wasn't the fic you were looking for. If it is, it can be found here at TSR.