CSS: Floating IMGs inside floating divs

CSS: Floating IMGs inside floating divs

I encountered a problem and didn't find a solution for this. I'm pretty
confused because I thought this was a very simple requirement.
there are the following elements:
a surrounding div#wrapper
div#A, floating left and fixed width
div#B, floating left (right of A) and dynamic width
Inside of div#B there are plenty of images, floating left and fixed width
(and height).
Depending on the screen resolution there should be 1, 2, 3, n columns of
images on the right part of the screen (next to div#A). Instead of this,
container B is aligned below container A and uses the full window width.
I would like to avoid absolute positioning because the height of the
surrounding wrapper should increase with its content.
To visualize what I'm talking about, I made the following diagram:
http://abload.de/img/rezeptbilder1k8lsr.png
Many thanks in advance!