You can also drag and drop the files directly into the website window to upload them automatically. To use I Love PDF, press the Select PDF Files button to select the PDF files you wish to compress.Most services work in a similar way, however, by allowing you to upload the file, select the quality, and download the compressed file afterwards. Various services exist to compress PDF files online, such as I Love PDF. Resample will reduce the file size by decreasing the number of pixels in the images present on your PDF. In the Optimized Images window, you’ll see three options here: Color, Grayscale, and Monochrome. This poses a serious security risk for any documents that may contain personal data, and you should only use online compression sites for files that you would be happy to share publicly. Here’s what you’ll need to know: Open the PDF. Using these services involves uploading the file to a remote server, where the file could remain in place for a period of time. Here’s what you’ll need to know: Open the PDF. If you want to use an online service like this, however, you should only do so with non-sensitive documents. If you don’t want to download additional software to compress your PDF file, you can use various online PDF compression services instead. You’ll need to open this in Preview afterwards to preview what (if any) noticeable changes in the quality have been made by the app. Preview will immediately save an updated, compressed version of your PDF document.