I really didn't anticipate that it takes me almost one day (actually it's from 5 pm to 12 midnight) to finish a simple Toon Boom animation, but it did.
Most of the time I spent was on figure out the best way to vectorized a few photos into vector art that is in manageable complexity for Toon Boom. The problem is that Toon Boom cannot handle graphics that are too complicate. 1000 vector lines seem to be the limit. Too much and the application may crash. There's always a temptation to try to preserver as much detail of the original picture as possible, but in reality I may need with lower color palette range, even though it means that I may need to alter the palette manually later.
I also found that .PNG jacks up the file size dramatically. Unfortunately there's no other option as only PNG support clean transparency. It jacks up the result movie size from 120K to 500+K .
Also, I cannot animate transparency of image like JPEG and PNG. So there's an incentive to convert graphic into vector.
Toon Boom cannot directly important Flash animation. So if I have graphic work done on Flash and need to move to Toon Boom, I have to export those art work into Adobe Illustrator format first. And even then Toon Boom may complain because the latest version of .ai exported by Flash CS3 is still too old for Toon Boom. My solution was importing the exported file into Adobe Illustrator CS3 first, and then export the graphic again into .ai (CS3) format. Now Toon Boom will be able to recognize the file and import accordingly.
It is very important to realize the difference between select and then rest of the transformation tools. Also pay close attention about whether you are animating the PEG or the artwork itself.
The color palette of the graphic imported into Toon Boom seems much shaper than the original palette while it is in Flash or Illustrator format. This is strange and may affect my final art.
On the plus side, I learned even more about Toon Boom and have a better understanding about it's limitation. It would be interesting if there's simply way to move Flash animation generated by ToonBoom into high end effect application, like After Effect or FinalCutPro Motion.