I think your hypothesis is right, that painting also appears in another photo of the visit, Kim Jong-un finds himself near a small jet engine, but the red arrow, despite the photo being partially censored, shows the drawing of a turboshaft engine, turboshaft unit structurally similar to the Klimov-Motor-Sich TV3-117VMA-SBM1, but smaller in size, perhaps intended for a training aircraft or a UAV/Drone, alternatively with 2 engines a light passenger/cargo aircraft .
View attachment 717719
PS:
I suspect that the model under the picture, always indicated by a red arrow, appears to be the reducer to connect the propeller and the jet engine indicated by Kim Jong-un could also be used to create the turboshaft/turboprop unit