Are there any offline navigation apps that support loading a map from an image?

I'm currently travelling in China and unfortunately Windows 10 doesn't offer to download offline maps for China... (this was possible before Win 10 wasn't it?).

I remember having an app for WP7 that allowed me to use an image for offline maps. I can't find anything like that though.

Does anyone of you here know an app that can do that (load map from image, set scale, show my position and heading on that map)?