In novaPDF Standard and Professional there is a Graphics tab that lets you select several Predefined graphic options. By default Compress is selected, which will compress the text and graphics when converting to PDF so that the size of the PDF file will be smaller. However, if you want to have a better image quality in the PDF file you can turn off text/graphics compression (size of the PDF will increase though).
To remove the Compress predefined filter:
Additionally, you can also change the DPI setting for the Graphics that will be converted in the PDF. This option is available for all editions of novaPDF. To change the DPI resolution for graphics:
Video Tutorial on improving the image quality: