The supposed photo of Rice in Hart's lap aboard a yacht was staged, on the pier not on the water. Hart was sitting down when Rice asked if she could have a picture with him, as is very common with Senators and Presidential candidates, ... and then she plopped herself in his lap and a buddy snapped the picture, all in a few seconds.
For the supposed "affair", she enticed two Miami Herald reporters to follow her around Washington, claiming she could prove that Hart was carrying on an affair with her (doesn't sound like she was much of a friend to Hart even then). Instead of riding in the same car with them, she had a taxi follow her directions while the Miami reporters were tailing her. She went into a door which was identified as Hart's ... and the reporters never saw her come back out although they waited until past dawn. She claimed to have spent the night. But the fact is that she had the cab drop her in the alleyway at Hart's kitchen door, having called Hart to tell him she was delivering money for his campaign (always something that will get you access to the candidate). Hart let her in through the backdoor and called a cab for her and showed her out shortly thereafter from the front door. No sex. But the reporters, being unfamiliar with DC, were not aware that they were watching the backdoor all night long.
A clever trick to use newspaper reporters to blow up a candidacy.