Just found out that the free Android GPS app OruxMaps supports .img files:
https://play.google.com/store/apps/details?id=com.orux.oruxmaps
Combine all the map tiles you want into a single .img file, then copy it into the mapfiles folder and select it as an offline map. Rendering isn't outstanding, but it does work.
https://play.google.com/store/apps/details?id=com.orux.oruxmaps
Combine all the map tiles you want into a single .img file, then copy it into the mapfiles folder and select it as an offline map. Rendering isn't outstanding, but it does work.