Gets or sets a value indicating whether images are decoded at the resolution they are drawn at rather than their own, for a
page shown much smaller than its images; false by default.
public bool ScaledImageDecode { get; set; }
For displaying only: viewers turn it on, and it must stay off for printing, export and anything that keeps the pixels as a faithful render. An image whose codec decodes reduced resolutions (DCT, JPEG 2000) is decoded at the largest power-of-two reduction that still leaves ImageSamplesPerPixel samples per device pixel along its most enlarged direction (GetReduction(in Matrix, Double, PdfColorConverter?)), which skips most of the decoding, converting and resampling of a large photograph shown on a phone. The rasterizer still box-filters the reduced samples to the device, so the page differs from a full decode only by the coarser average: at the default of 2 samples per pixel, 36 to 54 dB on photographs.
ISO 32000-2 §8.9.4 (image space and the unit square), §8.9.5.3 (Interpolate only affects enlargement, which a reduction never causes) and §8.6 (averaging before colour conversion equals averaging after it only for an affine conversion, so a curved conversion caps the reduction). Ignored with OverprintPreview, a print preview.