Using the "important" tag you can actually override inline styles using CSS. I suggest using this sparingly as it is not supported on all browsers. Example as follows.
.connectionBox {
height: 200px !important;
}
You could also perform the following core edit.
IN: components/com_comprofiler/plugin/user/plug_cbconnections/cb.connections.php
ON: Line 254
$boxHeight = $ueConfig['thumbHeight'] + 46;
The above is designed to be dynamic based on the maximum image height you've specified within CB configuration, but you can certainly edit as necessary.