If an user performs a simple search in Google using keywords like "mandelshtam princeton digital", one can come across an amazing digital discovery tool that provides access to Mandelshtam's digitized archive at Princeton University. The tool is called "Mandelshtam discovery tool". This tool can be accessed here.
Mandelshtam Digital Image Browser can be accessed here.
I have also created a library guide for Mandelshtam. It can be accessed here.