If you receive a PDF from your graphic designer and are not sure if it has been optimized then we recommend you follow these steps.
Open the PDF in Adobe Acrobat
Click on "Tools" located near the top right of the Acrobat screen. Then select "Create Links from URLs" under "Document Processing".
In the window that pops up, make sure "All pages" is selected and then click OK
Select the "PDF Optmizer" option, which can be found under File > Save As Other
In the window that opens select the "Images" option from the list on the left
Select the "Acrobat 5" from the "Make compatible with" option
Set the "pixel per inch" settings as highlighted in the image below
Select the "Transparency" option from the list on the left.
Set the Preset to Medium Resolution to acquire the settings listed below.
Select the "Discard Objects" option from the list on the left
Select all options
Select the "Clean Up" option from the list on the left
Select the "Optimize the PDF for fast web view"
When you press OK you will be asked to enter a name for these settings. In future you can automatically load these settings by choosing the name you enter from the list of "Presets" at the top left of the window.