Reducing the size of PDF attachments
Often when creating PDF documents, full resolution, full size images are included within the PDF document when saved.
This quality level is only required when sending down to a commercial printing press, and it can significantly increase the file size.
Reducing the file size on OS X
In this example the file size was reduced from 45.6Mb down to 1.2Mb
1. Open the PDF document in the Preview application
2. From the File menu, chooses Save As...
3. From the Quartz Filter menu choose Reduce File Size
4. Click the Save button