[OpenLayers-Users] Image flickering in Firefox when changing the URL of an image layer

[Marc Jansen]

Hi list,

when the URL of an imagelayer is changed via the APIMethod setUrl, the 
image is flickering regardless of the browser cache or the transition 
effect. This behaviour can be seen e.g. here:

http://www.webmapcenter.de/wetterradar/animation.html

In that demo the URL of the imagelayer is changed every 500 ms and the 
flickering should be easy to spot (at least if you wait for roughly 20 
seconds). Firebugs Net-tab shows that the images are being requested 
over and over.

The flickering is only noticeable in Firefox (3.5 Win and Linux); Opera 
10 and IE 8 work like a charm (they cache the varying images). The 
changing of the src of a pure <img> with JavaScript does not show the 
flickering (as can be seen in the above link, too). I don't have results 
for other browsers.

Can anybody help me identify the root of this flickering? I am unsure 
whether this Firefox bugreport is maybe relevant to this issue: 
https://bugzilla.mozilla.org/show_bug.cgi?id=492052. I doubt that it is 
related to apache settings (Caching- or Expires-Headers) as the pure JS 
solution isn't flickering at all.

Any help or advice on this issue would be great!

Regards,
Marc

BTW.: If someone shows me a better alternative to build an animation of 
different Imagelayers, I would be happy as well :-)