Yes, this is exactly what the evidence is implying. You have to remember that a lot of time there isn't a smoking gun so prosecution have to be careful about how they present the case so they are not giving the jury mistruths. What they can do is heavily imply that you should put 2 and 2 together to get 4.Im sorry if this upsets anyone so please hide my message if you wish.
Am I right in thinking he died from asphyxiation caused by oral sex? It would explain the bruising to his throat, and the finger bruises to his head, back of head and behind his ears. I cant believe I just wrote that. Its just too awful to comprehend someone would do that to a baby. They are absolute monsters.
This is what I believe they were doing with the bruising on Preston's head, followed by the photo of him in the cot. You our the two together to see how he got the bruises.