Other than looking in the Chinese manufacturer's website, which can be somewhat "misleading" (12.1 MP camera? come on...)
There's an app called Screen Resolution that will tell you the, ummm, screen resolution :) What device do you have, I have seen some specs for devices coming with a 12.1 MP camera, mostly by sony ericsson, but I don't think they are out yet, so it is possible that the manufacture is not lying.
You can visit this site from your phone's web browser which will show you your screen resolution, android version and device id.
You should be able to use
Settings > About phone > Hardware information > Display
E.g. on my phone, it says "3.7 inch WVGA resolution"
(Then of course, you would have to discover what WVGA is...)
The Hardware information screen should also tell you the camera specs too.
There are many sites you could visit (from the browser) that will give you this detail. Ex: http://ocupado.eu/info
There's another app called Device Discoverer that will give you a lot of information about your device. You can also send info by email or view your info on site. Info stored anonymously.
I'm the developer :)
I hope that will help you.
if you follow much the same path that Nick suggested, but instead go to
Settings > Display > Display Resolution it should show you the options for your screen resolution.
As for your photos, take a picture, put it on your computer and check the resolution. And let us know if you actually have a 12.1 MP camera!! :)