No, Draymond Green's so-called "Dick Pic" was not the result of his account being hacked. Green initially blamed the picture on a hacker, saying that a hacker had sent it out. However, he later said that it was in fact he who accidentally sent the picture. He said that it was supposed to be private.
It took too long for Draymond Green to declare that his account was hacked. First he just apologized, then he said he was hacked. His first response should have been sheer outrage that someone would do something so outrageous and claim he did it himself. I think the immediate damage control is a hint he made a mistake he doesn't want to live up to.
Anybody at all who has spent a lot of time online knows how easy it is to misclick and send a message to the wrong recipient or before you're ready for it to send. Clearly Green was just spending his time online the way millions of people do, and he simply got too excited and made a mistake. It happens every single day, just usually not to celebrities.
While Green initially posted on the social media site Twitter that his account had been hacked, he has since stated publicly that the picture was meant to be sent to someone in private. In response to the immediate criticism, Green recently proclaimed "We're all one click away from placing something in the wrong place. I suffered from that this morning."