Minecraft 1.16.5
Forge 36.1.30
Dimensional Paintings 1.16.5
JEI 7.7.0.104
Placebo 4.5.0
Toast Control 4.3.1

The portals don't link. I have made paintings within a few blocks of where you spawn as well as the same spot and they still don't link. Example: I place Nether painting. I go from Overworld into Nether. Break glass to make big enough space for painting. Place Overworld painting. Go through painting and end up further away than the original painting instead of coming back through the original painting location.