Hi!
Images are stored as they come. Reduce the size of the images to save bytes here; for JPEG images, save them with reduced quality to reduce the file size without changing image resolution.
If images contain only two colors, save them as bitonal (this allows PDFsharp to use the smallest possible image format).
Fonts are not embedded if you specify that:
Code:
XPdfFontOptions options = new XPdfFontOptions(PdfFontEncoding.WinAnsi, PdfFontEmbedding.None);
PDF files created with the DEBUG build are "verbose", so use a RELEASE build to see the real file sizes. All supported compression is on by default.