When showing an image using ~matplotlib.axes.Axes.imshow that has more than 2^{24} columns or 2^{23} rows, the image will now be downsampled to below this resolution before being resampled for display by the AGG renderer. Previously such a large image would be shown incorrectly. To prevent this downsampling and the warning it raises, manually downsample your data before handing it to ~matplotlib.axes.Axes.imshow