ORPALIS PDF Reducer Free is a tool which can take a PDF file and resample its images, omit unused objects and more, so reducing the file size while leaving it looking more or less the same.
To try this out you must first specify a source file and a destination folder, before clicking the "Start Batch" button. Early versions of PDF Reducer Free could be extremely slow, but performance now is much better, and the program compressed the 777 pages in our test files (some of which included very large images) in only 86 seconds.
Is it worth a try? In general, yes - especially for files with a lot of images. The program cut our most graphic-heavy document from 25MB to a mere 11MB in size. That level of reduction did involve significant quality loss, but the settings allow you to control this by setting your preferred image quality and resolution.
The program isn't just about graphics, though. Our smallest document was plain text, but ORPALIS PDF Reducer still managed to cut it from 20.2KB to 15KB; not as spectacular a figure, but still a very welcome 25% saving.
Please note, the program is free for personal use only, and has a nag screen to make sure you don't forget. Upgrading to the $199 Professional edition removes this, though, as well as getting you multi-threaded batch processing and "fully featured command line support".