Example image that is degraded by shot noise and easily misinterpreted?
Would something like Figure 4 in this paper by Dumitriu, Rodriguez, and Morrison (2011) work? They imaged the spines on a neuron using six different gain settings, which produce different amounts of shot noise. One can see how the putative shape of the spine changes based on the amount of noise present. This example might be a little esoteric for a general audience, but it does sound like you're doing some kind of microscopy, so perhaps it's a good fit.

Dumitriu, D, Rodriguez A, and Morrison JH. High-throughput, detailed, cell-specific neuroanatomy of dendritic spines using microinjection and confocal microscopy. Nat Protoc. 2011 Aug 25;6(9):1391-411. doi: 10.1038/nprot.2011.389.
Article at Nature Protocols