Please take a look at this file: https://drive.google.com/open?id=13AGoSPLVlIoybpZvSh2qxcjlKjXVSMyu
There is Gaussian Blur applied to the image, yet when the file is exported to PDF (for print) the blur is not working and the picture is pixelated: https://drive.google.com/open?id=1s-PMkgbh0c5cZdTS1JQ15Um316YYta1q