Can I draw overlapped pictures with transparent background?

Dear all,

I'm planning to draw some overlapped pictures on a tabpage.
I use PictureBox control. And the picture seems well at first.
But when I try to draw a PictureBox on the other.
The transparent part of the PictureBox seems to have the same colour
with the tabpage background.
And the PictureBox under it is covered by that.
The covered part is never seen again.
Can I simply solve the problem with existing simple control?
Or do I have use the directx api?

Any help would be appreciated.
Thanks in advance.