Even if you implemented something like inline css to reserve space using a min-height: parameter it would be better than nothing.
as an example, in a pro mosaic layout, we already specify how many images to show as well as row height.
in other options we also specify default thumbnail dimensions.
you could at least reserve space using min-height based on all the above settings we already set in nextgen to estimate at least some reserved space?
just a thought ??
