Convert Vector to Bitmap
Not only can you convert a vector symbol to bitmap when exporting in Flash CS5.5, but you can convert a symbol to bitmap on the stage by choosing Modify > Convert to Bitmap (among other methods). This converts the vector content on the stage to bitmap and adds a bitmap symbol in the Library (a bitmap version of the vector symbol), as shown in Figure 4. This is great for optimization in certain projects.
Figure 4 Convert vector to bitmap within Flash