Yes! You just fold over the little flap too and 
that's why I use the extra tape (the little flap 
has no adhesive on it). See the (really bad and 
hideously mis-sized) drawing below? The little 
flap (at #1) covers the rest of the edge. I put 
extra tape on the whole edges with the folded 
over flaps (where the #3 points to) and then I 
take the cut off flaps and put them on the edges 
where you see #2 pointing.

Now with the cut off flaps, I've found it's best 
to put them *inside* the box if there is room 
next to the cel since then there is no chance of 
them snagging on anything. But they can be taped 
on the outside - if you do, however, I would 
definitely make sure you tape *all* their edges 
so that the gradation between the surface of the 
flap and the surface of the rest of the box is 
smooth. ^_^

Hope that clears it up. ^_^  See what I mean? It 
is THE way to pack cels!

You know, guys. . . If we really put our heads to 
it, we could easily raise packing flat items to a 
fine art! ^_~~~~~~~~

Many Sharp Smiles,
--Drac