Both, just to be sure.
When I click on the nadir logo nothing happens at all, but the link itself works fine.
So I guess it has to be somewhere in the "onclick" command.
<hotspot name="nadirlogo"
url="nadir2.png"
keep="true"
ath="0"
atv="90"
distorted="false"
zoom="false"
scale="2"
rotate="0.0"
rotatewithview="false"
onclick="action(openurl(http://www.assetimaging.co.nz);)"
Does the onclick action here actually refer back to the nadir2.png?