I have foxit reader installed.
Thank you. but changing setting to Black & white even increases its size.
^I do this everyday. Reduces size from 8MB+ to <2MB. It works great.In Adobe Acrobat XI Pro, there is an option wherein you can re-save the file as 'Reduced Size PDF'. That reduces the size considerably while retaining quality.
If you mean reducing the size of the PDF you don't need to reduce image size, you can do it under the Documents tab (PDF reader like )as mentioned here:
^I do this everyday. Reduces size from 8MB+ to <2MB. It works great.