Multilevel Mixed Effects Models: Help Nesting Observations

I made an experingment were 100 individuals were exposed to 10 different situations (imagine they are watching 10 different paintings). For each individual and painting we measured variables like body temperature and heart rate (bpm). See here an example of data structure:

Imagine I want to predict individual nevrotism, based on people reactions to the different paintings. And I would like to design this as a Multilevel Linear Model with fixed or random effects (the mixed command in Stata).

I need help with the model design, as we have repeated measures on same people (not independent among them), but also reactions are driven by the painting content (so there is a dependence of variables inducted by paintings) How would you nest observations and interpret results? Would you make 2 or 3 levels? How?

UPDATE

Images are very different. Body response depends in part on the individual and in part on the image shown. So one image should slow the BPM and the other one should accelerate it, but still I want to use BPM to predict something else which is nevrotism.