That's what I am experiencing now. From the photo instruction it says "one (1) photo must ...." but didn't say what to do with the other one. This is a real trap and I got the whole package returned after 2 long months waiting with a letter attached saying the photo don't meet the spec but nothing specific. I checked the size of what they need, head placed in the centre, photos are sharp and clear with white background, natural expression without smiling, no glare, etc..... So desperate for the moment that they don't even mention what I have done wrong.
A while after I ran through some other Chinese forum and found someone got replies from CIC about the other photo, that must leave blank for PR card (same as what they did to Passport application) and got really shocked. I mean, when a good portion of people got similar mistake about the photo stamp they should clarify or even update the photo spec. at some point