Imported Images becomes choppy after resizing

Hi all,

Whenever I import a photo say 1000x1000pixels into flash cs3. it looks great, but however when i scale it down, i expected the quality to remain however it became choppy and unclear. I cant understand why is that so, because in Photoshop or Fireworks, when i scale down it just becomes smaller and doesnt become choppy.

Any help is greatly appreciated thanks!

Rgds,
Marc