see link
http://rsgallery2.net/component/option,com_smf/Itemid,17/topic,6860.0 , solution provided by Daniel Tulp, to aid in finding the relevant code that needs to be modified (for the Semantic template) :
change in siteroot/components/com_rsgallery2/templates/semantic/display.class.php
FROM:
if( $kid = array_shift( $kids ))
echo ',';
else
break;
TO:
if( $kid = array_shift( $kids ))
echo ',<br/>';
else
break;
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