I find this difficult to believe; no matter how small your camera is, photography is about light. Art reproduction photography is surprisingly hard to do if you care about the quality of the end result. Unless you can surreptitiously smuggle in a studio lighting setup, tripod, and color checker card… sure you can take an image in secret, but not one that is a good representation of the real thing.
You could just build a stabilizer system and stand really still for 1 second. Then expose for a longer time. Photography is Apertrue, ISO, and exposure time. This will gather enough light to do a proper exposure even in a dimm lit venue. Anything darker and every viewer will have a hard time seeing the private art.
ANother thing would be to crank up the ISO and denoise it later. Its much more lossy but with this you could get lower exposure times.
It’s about number of photons and aperture. In principle this could be very hard to detect, especially once people get good at multiple distributed apertures that are coherent with one another.
