Hello,
I'm having a problem... I have an wms server and when I had it as a simple OpenLayers WMS there is no problem.
But I need to be able to load the images at server side so I use the WMSRaster Layer, but the there seems to be applied some compression.
I've made a simple sampe and a small video (look at the last part).
I also made the WMS available so you can use it in your tests.
Please look at: ruilima.com/?attachment_id=136