Gary S,after the snapshot in pfd format I just open PS and go from there.
If you wanted to you could use "preview" to change the format from pdf also.
Although that is just another option.
Take the snapshot (com+shift+4 or whatever) and open the pdf with "preview".
Then go up to the menu in preview - file>export.
Examples:
One and
Two.
Like I said ... just another option because if you wanted to 'shine' it up some,you'd have to run it through PS,painter etc etc anyhow.