Smoothing image sequence

1st time poster. I am new to Vegas Pro (using 9). I have followed the several threads started by Hans-Joachim on May 2009. I am importing about 720 .png images into Vegas to create a video. Thanks to all the wonderful post's, I have managed to come up w/ a somewhat decent video. However, the video still runs like a "rainbird" (small jerky motions). I tried to capitalize on Mike Kujbida post concerning still image length, overlap & overlap conversion. However, w/o knowing exactly what each of these settings does to the video, it is hard to adjust accordingly. I have tried the help glossary in Vegas as well as the same in the user manual, but cannot seem to understand how to use “crossfade”, “dissolution”, etc. to my advantage. I am certain that Vegas can produce a smooth video from a sequence of images, but how to get there & why is beyond my ability. Help?
P.S. the images were exported as .png out of a Google Sketchup Pro file.