That map clue had me with my head sideways.. I knew pretty early on the basement served more purpose, just didn't connect the painting with the basement until Unniex mentioned it.
Your return clue: Imagine your in a dark room, the only things you can see is not very much. I usually have to run my hands against the wall to be able to tell where they are (or aren't).
Once you find Yuri, unless you're going for the male route, you should return to where you found here at least once.