Top panel: histogram of all pixels across a 200 arcsec² region from a VIS detrended image. The histogram shows regular spikes at the 1 ADU frequency, indicative of quantisation noise (this effect is also observed in the raw data). Bottom panel: same region after resampling the detrended image with SWarp using a Lanczos3 function. The histogram shows that the pixels have been correlated and the quantisation error has been smoothed out.