(SPOILER) The ending.. What I really think
I think John Taylor didn't send the photo to detective Morton. I think it was the lieutenant himself sent the photo so that he can use it as an excuse to call the detective over for a real dinner. But if it is, clueless what he will do to the detective. Why I suspect it's him? John Taylor was nowhere getting hold of a picture and he was thrown outside by the lieutenant in the garbage dump and sure he will make sure Taylor is stripped search considering the lieutenant meticulous nature.
Another possible scenario :
Taylor did send the picture and the detective was invited for a dinner by the lieutenant was actually just a gimmick. See that the lieutenant quickly pack his bag and went outside. He wasn't really going to have another phantom party. He was going home to destroy all evidence and pack up and leave to Mexico where he can live the rest of his life by eating tacos and having phantom party.
Another one :
Yes it could be what the ending is, Taylor did send the photo. How did he get it , I have no idea? But really now the lieutenant is in trouble and I do not think the detective is that stupid to go there alone. He has a sense of suspicion with the lieutenant's story.