PeachPDF
PeachPDF.PdfGenerateConfig
PdfGenerateConfig.DownscaleImages Property
When set to true (the default), a raster image whose decoded pixel size is larger than
its on-page display size is resized down before being embedded in the PDF, shrinking output
file size with no visible quality loss. Set to false to always embed images at their
full decoded resolution, as PeachPDF did before this option existed.
public bool DownscaleImages { get; set; }