Can't remember the kid's magazine where you spot the differences, but I notice:
On the T4i...
1. No microphone on the front.
2. Front buttons don't look as recessed (see flash/DOF buttons).
3. Function dial has a different texture--no lock, great!
4. Button arrangement around said dial looks different.
5. Side covers look the same to me, front is remote control and mic, rear is A/V out and HDMI mini out.
6. Overall a more chiseled look...less rounded off.
7. Something is going on in front of the hot shoe...left and right...stereo mic perhaps?
Edit: It's "Highlights," and you don't compare two pictures, you have to find hidden items in a sketch.