Google-chrome – How to make Google Chrome save PDF files without opening a second window

You can set the auto-open preferences for PDF files by clicking on the download status button in the downloads bar. When you have a downloaded PDF sitting there, click on the arrow and unselect "Always Open Files of This Type" in the pop-up menu.

You can also reset all the user preferences for auto-open by following the directions below from Chrome's help site at http://support.google.com/chrome/bin/answer.py?hl=en&answer=95759

If you want certain types of files to always open after they're done downloading, click the arrow next to the file button in the downloads bar and select Always open files of this type. To prevent potentially malicious files from automatically downloading to your computer, this option isn't available for executable filetypes, such as those with .exe, .dll, or .bat extensions (for Windows), and .dmg extensions (for Mac).

You can clear auto-opening settings through the Settings dialog. Here's how:

Click the wrench icon on the browser toolbar. Select Settings. Click the Under the Hood tab. In the "Downloads" section, click Clear auto-opening settings. This clears your settings for all file types. Click Close when you're done, if you're using Windows or Linux.

I'd say, the size of a PDF is directly related to quality of the picture within it. I'm guessing first program saves from PSD to PDF with best possible quality. You could search for any options that could lower quality, and decide if output was satisfactory.
I'm also using printong to PDF by means of Bullzip PDF or Primo PDF, they both have some means to lower quality upon printing. I guess you just have to experiment.