Quote - So if I understand Dizzi correctly, let's say I have a texture map of 4000x4000 (seems to be what most vendors make textures at.) and I set the max texture size to 2000.  Then poser will automatically shrink the texture image by half?  (At the begining of the rendering prosess when it says "Loading Textures".)

Yes, but it'll of shrink it to a fourth (and the memory consumption will be 1/4th, too ;-)) > Quote - So then what does Texture Filtering do when it is on/off?

See manual page 339. It's got an example picture there, too. In Poser 5/6 that'll take roughly 3 times as much memory as without texture filtering. You'll also find people saying that it'll improve the look of hair textures, too - but usually reducing the resolution of the texture in an image editor also does this (and AFAIK Poser 5/6 does the same: create a bunch of lower resolution textures for texture filtering - thus the high memory use).