Question: Is it possible to resize a bitmap image sized 9000x9000 to 150x150? I've heard there are some limits...

Answer: 
> 
> BitmapData: Flash CS5 ActionScript
>  3.0 Language Reference
> 
> 
> In AIR 1.5 and Flash Player 10, the
>  maximum size for a BitmapData object
>  is 8,191 pixels in width or height,
>  and the total number of pixels cannot
>  exceed 16,777,215 pixels. (So, if a
>  BitmapData object is 8,191 pixels
>  wide, it can only be 2,048 pixels
>  high.) In Flash Player 9 and earlier
>  and AIR 1.1 and earlier, the
>  limitation is 2,880 pixels in height
>  and 2,880 in width.
> 
> 
>
PNGEncoder

9000 shouldn't be too high

open the image and then use the PNGEncoder to save the image back out.