When adding an account in Windows 10, the default account picture will be used as the account’s picture by default until the user changes their account picture or when their Microsoft account picture syncs.
This tutorial will show you how to change the default account picture used for new accounts in Windows 10.
1 Open the folder below in File Explorer (Win+E).
%ProgramData%MicrosoftUser Account Pictures
2 Rename the user.png, user-32.png, user-40.png, user-48.png, and user-192.png files to add .bak to the end of their file name extension as user.png.bak, user-32.png.bak, user-40.png.bak, user-48.png.bak, and user-192.png.bak. (see screenshots below)
3 Copy the PNG file you want to use as the default account picture into this folder, and rename it as user.png. Repeat this process until you have copied and renamed for the other user-32.png, user-40.png, user-48.png, and user-192.png files. (see screenshot below)
4 Sometimes you may need to restart the computer to fully apply.
