I recreated your script for my needs and after realizing I needed to add + '.gif' it all came together - thanks!
Is there anyway to add Tool tips functionality?
SELECT a.DisplayName as Application, n.caption as Node,a.DetailsUrl AS [_LinkFor_Application], '/Orion/images/StatusIcons/Small-' + a.StatusDescription + '.gif' AS [_IconFor_Application],'/Orion/NetPerfMon/NodeDetails.aspx?NetObject=N%3a' + ToString(n.nodeid) AS [_LinkFor_Node]
FROM Orion.APM.Application a
join orion.nodes n on n.nodeid=a.nodeid
join orion.containermembers m on a.nodeid=m.memberprimaryid
join orion.container c on m.containerid=c.containerid
where c.name = '${caption}'
ORDER BY a.status DESC