StartIsBack on Windows 10, user picture frames

[leanderthal]

See the attached picture, please. Where can I locate the file with the default round user frame (red arrow)? This is so I can replace it with my own (green arrow). In the past, with other versions of Windows, like Windows 7 for instance, the user frame can be found in authui.dll, shacct.dll, and explorer.exe, but that is not the case anymore with Windows 10. Thank you.