JPEG compression ratio compared to a third party tool.

Q: I want to place a jpg on new page in a new doc and save it. Using
the default PDFNet settings the resulting pdf is just slightly larger
then the original jpeg image, and was told by your support that this
sounds normal. But my company has used other tools and come up with a
pdf that is about the ½ the size of the original jpeg image. I was
asked to send you the jpeg image the original output pdf from our
other tools (CVision) and you might be able to help us.

Attached is a zip files containing the jpg image and the original pdf
(not one created from your SDK). Please let me know if I can achieve
similar compression.
A: We looked into the PDF file generated using the third party tool
and we found that embedded image is compressed using JPEG compression.
Despite of their claims, the only reason why there is a reduction in
file size is because of "lossy" recompression during image import. To
verify this open the sample PDF in Acrobat Reader and zoom-in on a
single character in the test file. You will notice fuzzy, pixilated
area surrounding each glyph. By default, PDFNet SDK preserves the
original image quality during image import. Please note that using
PDFNet SDK you can also recompress image and decrease the file size
using JPEG & Quality hint paramter, however this option will result
in loss of image quality.