Recent rate distortion analyses of image transform coders are based on a trade-off between the \emph{lossless} coding of coefficient positions vs. the lossy coding of the coefficient values. We propose spike processes as a tool that allows a more fundamental trade-off, namely between \emph{lossy} position coding and lossy value coding. We investigate the Hamming distortion case and give analytic results for single and multiple spikes. We then consider upper bounds for a single Gaussian spike with squared error distortion. The obtained results show a rate distortion behavior which switches from linear at low rates to exponential at high rates.