IronPDF supports compression of PDFs. The way in which the majority of PDF file size can be reduced is by reducing the size of embedding images within the PdfDocument. Therefore, we can call the CompressImages method.
The way resizing JPEGs works, 100% quality has almost no loss, and 1% is a very low quality output image. Generally speaking, 90% and above are considered high quality, 80%-90% is considered medium quality, and 70%-80% is considered low quality. Reducing below 70% will produce low quality images, but doing this may reduce the total file size of the PdfDocument dramatically.
Please experiment with different values to get a feel for the range of quality versus the file size to get the optimal balance for your requirements. Obviousness of quality reduction ultimately depends on the type of image that was input, and some images may reduce in clarity more significantly than others.