Oil paint is in general not really good for long term storage. It expands as it oxidizes. Some pigments slow down or speed up this process. The thicker the laye

Oil paint is in general not really good for long term storage. It expands as it oxidizes. Some pigments slow down or speed up this process. The thicker the layers, the faster they will crack. Combined with a lot of untested pigments and techniques, the art of the 19th and 20th won't last as long as pre-industrial art. 600 year old egg tempera paintings are often in better condition than 300 year old oil paintings. And now I will back-up some jpegs to a usb stick that probably won't survive a single decade...