vaderios said:

And secondly if the AT-ATs are so low how the heck can fire at snowspeeders in straight lines. Arent the lasers supposed to be from the ground(aka Walkers)?

This is an interesting one too vaderios.

The shot shown at the bottom here comes at the point where Luke says "Rogue Three" just soon after General Veers has told Vader's hologram that he can start his landing....and at about 45 seconds before this shot, we can also see a similar, small, 'lower-down' AT-AT in the distance during the shots where Luke says "All right, stand by, Dak", and then where Dak replies "Oh, Luke, we've got a malfunction in fire control"....

While the height/angles of all the various other AT-AT laserbolts seen firing at Speeders during the rest of the battle seem fine....the horizontal ones in these particular 3 shots do indeed seem to make it look like they are coming from off-screen AT-ATs that are too high up, when compared to the height of the AT-AT seen in the distance....

So unless the off-screen AT-AT's that are firing at the Speeders in these 3 shots are supposed to be on a steeper incline on the snowplain than the small, distant one somehow....then perhaps Adywan can re-'angle' the trajectory of all these laserbolts a little....although I'm not sure if the small, 'lower-down' AT-AT should be seen in all these shots anyway....considering the footage afterwards makes it seem that the Speeders travel a fair distance before they come to the ones that are firing at them....