When you embed digital photos and other media into an Adobe PDF file, by default Acrobat includes the entire photo. If you include lots of photographs, your PDF file can rapidly grow to be huge, making it hard to distribute to people via e-mail or the web.
As of Acrobat 8, there is an option to save PDF files in an "Optimized" fashion, which makes them much smaller. To save an optimized PDF, open the file in Acrobat, and then click File and then Save As. In the box labeled "Save As Type", select the option labeled Adobe PDF Files, Optimized (*.pdf). Be sure to give your PDF file a new name - we strongly recommend that you keep one copy of the ORIGINAL document, and one copy of the OPTIMIZED document, in case you ever need to use a higher quality version. Then click Save and you're done!
For advanced users, you can click the "Settings" button at the right before you click Save. There are a lot of options there that allow you to adjust the settings when saving the optimized PDF file. However, for most e-mail attachments and web uploads, the defaults will be fine.