would this poss be the problem
;;;set_ajax_obs('ajaxProgress',rand+'rose','in WindRose');
if (gust > 0.0 || wind > 0.0 || wrImg.calm=="") {
windicon = '<img src="' + imgDir + windDir + '.gif' // small arrow direction
+ '" alt="' + langWindFrom + valLang
+ '" title="' + langWindFrom + valLang
+ '" width="14" height="14" />';
set_ajax_obs("ajaxwindicon" , valLang, windicon);
set_ajax_obs("gizmowindicon" , valLang, windicon);
set_ajax_obs("ajaxwinddir" , valLang);
set_ajax_obs("ajaxwinddir2" , valLang);
set_ajax_obs("gizmowinddir" , valLang);
set_ajax_obs("ajaxwinddeg" , windDeg + uom.Deg);
set_ajax_obs("gizmowinddeg" , windDeg + uom.Deg);
maybe change the gif to png ?