When I was thinking about different image porn boards to include, 420Chan.org was one of the first places that came to mind. This place was around when I was just a stupid teenager, and I used to browse there regularly in order to find porn that was relevant to my interests. It follows the same style of content distribution as the classic 4Chan, although has some boards that aren't available for posting that you won't find anywhere else.
The /sa/ board for straight adult porn is typically where I start my journey, but feel free to branch off into other avenues of adult entertainment if that floats your boat. 420 Chan also has a gay board as well as a place for hentai - who doesn't love some animated love of boy on boy action?
Oh, and as the name might suggest, 420Chan is also heavily focused on the discussion and support of drugs. You'll find that it's not just limited to weed either. These guys just love their pills and powders.