regarding the infrared effect (Night vision) the rabbit mentioned that idea just to group the flames which may imply that evey flame you can see with infrared is a real flame (1) the others (0)
when you apply the infrared effect (which means you can see at night without any light) then the image looks like this: (Green colour is dominant)
https://imgur.com/a/tQC0Wthat particular effect doesnt do a great job of bringing much out.. one thing i noticed is that if you do a simple invert operation in gimp, the background to the flames comes out as a row of more standard-looking flames, with the white-orange-red sort of coloring..
https://imgur.com/a/YItrzThese types of analyses seem futile to me. She painted this particular painting by hand. I don't see infrared effects or other filters being useful here. If anything, this is a puzzle about correctly interpreting symbolism.
Symbolism and all of these cloud reading efforts are futile, in my opinion. Whatever is hidden, and however it is hidden, is likely encoded in a way that is not open to interpretation or ambiguity. Or at least that's how I would design it. What is the
least ambiguous element of the puzzle in my opinion? The colors of the flames, and whether or not they are tall or short. The orange squat flames are ambiguous, I'd say. Along with the thick/thin angle people are going for.