lainyrache on "caching with old galleria script"

Can anyone advise some direction to try for caching custom thumbnails?
I have a site with an old galleria script integrated. The images are loading a bit slowly in the thumbs list view.
Is there a way to preload via zenphoto that I am missing?

I am using
<?php printCustomAlbumThumbMaxSpace('','300',200,'portraitalbum',20,true); ?>
and
<?php echo getCustomSizedImageThumbMaxSpace(300,200); ?>"

I can see in cache manager and tried setting a 'maxspace' as described there but it makes no difference.

'Some themes use MaxSpace image functions. To cache images referenced by these functions set the width and height parameters to the MaxSpace container size and check the MaxSpace checkbox.'

Do I need some custom coding or am I missing something obvious in the settings? Any guidance much appreciated.