How to modify the height of collapsible block regions?

Hi

When I add a block 'A' with a image that is about 100 pixels in height to the 'above' block region, I can not see the block 'A' as the height of 'above' block region doesn't increase to accomodate the height of the image.

On the contrary when I add a narrow strip of text to 'User 1, 2, and 3' block regions, I the height of the block that I get is 3 to 4 times the height of the text strip.

How to modify the height of the collapsible block regions with particular reference to above and user blocks.

Thanks for a wonderful theme.

Whitesun