Comment 1 for bug 854670

> (a) the snapshot images being displayed upside down

I have never seen this before, and it could be an indication of a broken driver. Could you post a screenshot of this so I know exactly what you mean?

> (b) when you are using multiple monitors, the snapshot images are displayed in between the two monitors (i.e., in the center of the combined space, rather than in the center of one monitor).

Do windows maximize over the two monitors as well? Usually the only case where this will ever happen is where compiz detects one single monitor, and that would only ever happen if X was telling us that there was only one physical monitor

Could you post either your:

 1) xrandr --verbose if you are using the intel, radeon or nouveau driver or
 2) nvidia-settings -q all if you are using the proprietary driver

That will tell us what your driver thinks the screen layout is and then we can narrow this down from there.