I read through the whole thread and that one hint (the Xs and their sequence) were never used to solve anything, also I find it awkward that the chessboard was considered in the thread before it actually appeared on the painting. It is kind of too much of a coincidence. Then again, it may be an awkward coincidence...
Are you referring to the sequence below? It was the beginning of the ARG and led to the 1follow address. The reason someone considered it as a chessboard was because there were chess references in earlier parts of the ARG, even before this image. I wouldn't expect this to related to the image though.
-=[O]=-=[ ]=-=[ ]=-=[x]=-=[x]=-=[ ]=-=[ ]=-=[x]=
-=[ ]=-=[x]=-=[ ]=-=[ ]=-=[x]=-=[ ]=-=[ ]=-=[ ]=
-=[x]=-=[ ]=-=[ ]=-=[ ]=-=[ ]=-=[ ]=-=[ ]=-=[ ]=
-=[ ]=-=[ ]=-=[ ]=-=[ ]=-=[ ]=-=[ ]=-=[x]=-=[ ]=
-=[ ]=-=[ ]=-=[ ]=-=[ ]=-=[ ]=-=[x]=-=[ ]=-=[ ]=
-=[ ]=-=[ ]=-=[ ]=-=[x]=-=[ ]=-=[ ]E-=[M]=-=[ ]=
-=[x]=-=[ ]=-=[ ]=-=[x]=-=[ ]=-=[ ]=-=[ ]=-=[x]=
-=[ ]=-=[ ]=-=[ ]=-=[x]=-=[ ]=-=[ ]=-=[ ]=-=[ ]=
-=[ ]=-E[x]=-=[ ]=-=[-]=-=[3]=-=[4]=-=[7]=-=[ ?
O = Origin Block
M = Message
E = Error in separators
? = Missing close square bracket
Also there was this comment
Ok this one is pretty obvious but I have not think about it until now.
The first message has two series of numbers the encoded in the X and the 347 final part, maybe that's the user and password and we just need to properly decode both.
3 4 7 9 12 16 30 37 43 48 51 55 59 65 - 3 4 7
(...)
I think that series may be important later on, but it isn't part of this password puzzle.
(...)
and mirth23 knows what he is saying, he solved a large part of this puzzle. If this painting is really the last puzzle piece, than when to use the sequence if not NOW?
This is possible. The number 347 in particular has shown up many times throughout this series. If applying it to the flames, I'd guess you could try looking at every third flame, then every fourth, etc. Are there other ways this number sequence could relate to the image?