opacity bug on smartphone...

here is the blit result of the same bitmap 4 times :
I think there is something wrong :(
the bitmap is a gif, 40pix width & height. Opacity is set to 200, but the problem is the same with 128 or anything else.
The problem appears on the real phone AND the emulator.
(the white box is drawn on the top of the bitmap)

I think there is something wrong :(
the bitmap is a gif, 40pix width & height. Opacity is set to 200, but the problem is the same with 128 or anything else.
The problem appears on the real phone AND the emulator.
(the white box is drawn on the top of the bitmap)