After add images to drawable "Cannot resolve symbol R" issue not going away after clean, rebuild etc

I can't find a way to add images to drawable folder without getting "Cannot resolve symbol R" issue.

And once i get "Cannot resolve symbol R", I can't get rid of it by either clean, rebuild, sync, invalidate cache & restart solutions for the error. Only if i delete the files can I get the build to pass.

I am not sure what is wrong here.

Note: I am on Android Studio 2.1.1