"Signature field(s) detected" in Adobe reader

I found it quite annoying that a green banner showed up in  Adobe reader every time I compiled a pdflatex file. To prevent this green banner from showing up, I found the instruction in this link (http://try67.blogspot.com/2013/05/acrobatreader-disable-sign-pane.html) which suggests a registry trick to set "HKLM\SOFTWARE\Policies\Adobe\(product name)\(version)\FeatureLockdown\cServices\bEnableEchoSignDetection" to 0. Unfortunately the key was not there on my laptop. I had to create the key and then the value by hand. Note that the latter should be created as a DWORD.

Reduce size of PDF files with embedded JPEG

I found this fantastic feature of ghostscript:

gswin64c -sDEVICE=pdfwrite -dNOPAUSE -dBATCH -dPDFSETTINGS=/ebook -sOutputFile=C:newFile.pdf C:originalFile.pdf

Sources:
http://www.itechies.net/blog/archives/1764
http://www.alfredklomp.com/programming/shrinkpdf/