I agree with you Ed and I too remember previews.  I guess I am showing my age as well!

When one goes to a movie theater, previews are shown depicting samples of upcoming movies.  (You can tell I'm old.  We called them previews, younger folks call them trailers.)
 
The thought is this: What we are seeing are not the opening of seals.  We are seeing previews of things to come.  These are the warnings in the form of a small sample of what is actully going to happen, on a massive scale, once those seals begin to open and the viles are poured and the trumpets blow.  Just a pinch of what is to come.
 
So we can say to the non-believer...all of these things you're seeing...imagine them on a vast scale.  Not deadbirds in a few locations, but everywhere.  Same with the fish, the cattle, and the creepy crawlies.  The floods you're now seeing?  Nothing compared to what is to come.  And the earthquakes, and all of the other manifestations which are now being shown on a very small scale, comparitively speaking, to the disasters to come once Jesus removes the believers from the earth.
 

Keep looking up!
David