Cant figure this one out 4 the life of me

If you go to this site:
http://www.allowe.com/sight/gags.htm?j=550

...and keep hitting next until you get to the image which shows 12 men - then the top of the image switches sides and there are 13. Someone give me the answer to this one.

antony schrieb:

Look at the men whose feet are almost on the line, and the men whose hats are almost on teh line. Check to see where the smallish body parts are beofre and after the switch.

Would it help to remove the seeming paradox if you noted that when there are 13 of them each of them is 12/13 as tall as when there are 12 of them?

Imagine each man is composed of the TOP and BOTTOM part, measure each part and write it down.

You'll get something like this

TOP: 1 6 10 3 8 0 4 9 2 7 11 5 9 BOTTOM: 10 5 1 8 3 0 7 2 9 4 0 6 2 HEIGHT: 11 11 11 11 11 0 11 11 11 11 11 11 11

every man is 11 [units] tall except the 13th man (the 6th column), who is 0 [units] tall

Now switch sides:

TOP: 0 4 9 2 7 11 5 9 1 6 10 3 8 BOTTOM: 10 5 1 8 3 0 7 2 9 4 0 6 2 HEIGHT: 10 9 10 10 10 11 12 11 10 10 10 9 10

now the average height is 10.15 [units].

Thanks Pedro - This is the easiest way I have seen it explained - my headache is finally going away