The picture is simple. She's holding an absolutely massive seashell that she found on the beach, and she's got this grin on her face, like she's won the lottery or something. He's in the corner, laughing at something stupid Embry had said.
That day seemed like it happened last week, and it probably could have, considering how often he and Bella had gone to the beach. But that day was special, this picture is special. You can't see it at first glance, but there's a ring on Bella's ring finger. It isn't glinting in the sun or anything, and it isn't big, but it's there. That's really all Jacob could have asked for.
She had laughed a lot when she was with him. She had laughed at the dumbest things that would pop out of his mouth, things that weren't funny at all. Jacob wondered if that was because she had never laughed in her other relationship, so she was simply catching up on lost time. The camera doesn't catch it, but the second this picture is snapped Jacob is going to grab Bella and spin her around. And she's going to clutch her seashell to her chest and laugh.
Jacob squeezes his eyes shut. He doesn't like what's in front of him. He never will. But he wants her to have this picture. It's not just any picture. It expresses them. Their happiness, their sadness, their imperfection; but to Jacob, their imperfection was what made them perfect.
So he digs a little hole into the ground, sets the picture inside, and covers it back up. This is where Bella will lay from now on, and someday he'll come lay beside her forever.
He won't miss the picture, because he has a spare. It's framed and sitting on top of his bedside table, right next to Bella's seashell.