For alpha channels use .png they are much smaller. Alpha channel works a bit different in llightwave than in shockwave, alpha channel in lightwave will make the base texture show through (or another texture) but will not give you transparency unless you map a transparency map in the the appropiate channel. In shockwave the alpha on the color texture will show up as transparent. You can also use tga, but I use PNG for the lossless compression, if the image has no alpha I use jpg. Most of my scenes have both.
Looking at your image again, you can also avoid the blury ground by using a pair of tiled textures on two surfaces, one for the grass, another for the trail. It will look nicer and load faster.
As far as literature.. well I haven't found much.. there are good (if a bit dated) director tutorials in:
http://www.deansdirectortutorials.com/
I don't use director myself I just hand the w3d file to a programmer and he does the rest, but through trial and error we have come to find a few things that work. The file size of the finished movie is mostly images and code so don't worry too much about geometry, we have a few scenes with over 10,000 polygons that run fine on an average computer.
Looking at your image again, you can also avoid the blury ground by using a pair of tiled textures on two surfaces, one for the grass, another for the trail. It will look nicer and load faster.
As far as literature.. well I haven't found much.. there are good (if a bit dated) director tutorials in:
http://www.deansdirectortutorials.com/
I don't use director myself I just hand the w3d file to a programmer and he does the rest, but through trial and error we have come to find a few things that work. The file size of the finished movie is mostly images and code so don't worry too much about geometry, we have a few scenes with over 10,000 polygons that run fine on an average computer.