Handle super big bitmap(s)

Hello there!
I’m creating a program that is loading tons of small pictures. (4000 pictures).
I am adding pictures into a bitmap*COLOR=#40e0d0[/COLOR]* with bitmapData.draw().
Everything works well until I *Zoom *the bitmap too much, when I *zoom *the bitmap grows.

When the bitmap is around 20000x20000 this error is displayed:
[COLOR=#ff0000][Fault] exception, information=ArgumentError: Error #2015: Invalid BitmapData.
[/COLOR]
The problem about this is that 20000x20000 isn’t even nearby of what I’m going to need, so I thought of a solution to add several bitmaps with a maximum width & height of 20000 and yep, it worked… But!
It’s barely possible to navigate around because of the number of bitmaps (…much lag)
I usually draw them with bitmapData.draw([COLOR=#40e0d0]PictureBitmap[/COLOR], matrix), the matrix is the same size as the stage. (800x800)

So finally my question:
How would you display these pictures?
It’s about 100000x100000px together.

Thanks in advance,
Tompa