Snarl appears in three shots in Transformers The Movie.

#1: Dino mode - Autobot City. When the Autobots are receiving communique from Moonbases 1 and 2 and deciding to fly and stop Unicron, Snarl can be seen standing with the other Dinobots/Autobots. He's next to Grimlock and behind Perceptor on the right hand side of the screen when the Autobots/Dinobots are facing stage left.

#2 Dino mode - Autobot City. When the Decepticons begin attacking Autobot City, just before Ultra Magnus says "to the shuttles!" and you see the Autobots below being shot at, Snarl is amongst them. He is on the mid-left of the screen.

#3 Robot mode - Quintesson cruiser. As the Quintesson cruiser carrying Hot Rod, Kup & the Dinobots is landing on the planet Junk - as you see it corkscrewing in descent, you can see the Dinobots standing on the bridge, Snarl is amongst them.

That's it. They're very brief appearances and you'll probably need to use the freeze-frame/slow-play function to see him properly.