i got these high quality pictures...and i made them uncompressed with an alpha channel. Is it possible to turn the alpha channel on in DVDA2? so i can get rid of the black background??
DVDA is a DVD Authoring program, not a general purpose editing program. Create your content in Vegas (which understands alpha channels), then render it out as an MPEG-2 stream using one of the DVDA templates - use the resulting MPG file (and AC3 if appropriate) in DVDA.
That depends -- what are you trying to do with them in DVDA? If you're adding them to a menu, you don't have to do anything. DVDA will leave the alpha channeled portions transparent. If you're adding them to a picture compilation, exactly what would you expect to show for the alpha channel if not black? ;-)