Hi,<br>The following issue has been observed with MapServer 6.0.3:<br><br>1. Very good quality for a PNG with RESAMPLE=BILINEAR and OVERSAMPLE_RATIO=16:<br><img class="" alt="http://wms-bgdi.bgdi.admin.ch/?lang=xx&LAYERS=ch.swisstopo.pixelkarte-grau-pk100_bazl&FORMAT=image%2Fpng&SERVICE=WMS&VERSION=1.1.1&REQUEST=GetMap&STYLES=&SRS=EPSG%3A21781&BBOX=513184,143152,519840,149808&WIDTH=256&HEIGHT=256" src="http://wms-bgdi.bgdi.admin.ch/?lang=xx&LAYERS=ch.swisstopo.pixelkarte-grau-pk100_bazl&FORMAT=image%2Fpng&SERVICE=WMS&VERSION=1.1.1&REQUEST=GetMap&STYLES=&SRS=EPSG%3A21781&BBOX=513184,143152,519840,149808&WIDTH=256&HEIGHT=256"><br>

<br>2. Less good quality for a PNG or JPEG with default resampling settings:<br><img class="" alt="http://wms-bgdi.bgdi.admin.ch/?lang=xx&LAYERS=ch.swisstopo.pixelkarte-grau-pk100_original&FORMAT=image%2Fpng&SERVICE=WMS&VERSION=1.1.1&REQUEST=GetMap&STYLES=&SRS=EPSG%3A21781&BBOX=513184,143152,519840,149808&WIDTH=256&HEIGHT=256" src="http://wms-bgdi.bgdi.admin.ch/?lang=xx&LAYERS=ch.swisstopo.pixelkarte-grau-pk100_original&FORMAT=image%2Fpng&SERVICE=WMS&VERSION=1.1.1&REQUEST=GetMap&STYLES=&SRS=EPSG%3A21781&BBOX=513184,143152,519840,149808&WIDTH=256&HEIGHT=256"><br>

<br>3. Awful quality for JPEG with RESAMPLE=BILINEAR and OVERSAMPLE_RATIO=16:<br><img class="" alt="http://wms-bgdi.bgdi.admin.ch/?lang=xx&LAYERS=ch.swisstopo.pixelkarte-grau-pk100_bazl&FORMAT=image%2Fjpeg&SERVICE=WMS&VERSION=1.1.1&REQUEST=GetMap&STYLES=&SRS=EPSG%3A21781&BBOX=513184,143152,519840,149808&WIDTH=256&HEIGHT=256" src="http://wms-bgdi.bgdi.admin.ch/?lang=xx&LAYERS=ch.swisstopo.pixelkarte-grau-pk100_bazl&FORMAT=image%2Fjpeg&SERVICE=WMS&VERSION=1.1.1&REQUEST=GetMap&STYLES=&SRS=EPSG%3A21781&BBOX=513184,143152,519840,149808&WIDTH=256&HEIGHT=256"><br>

<br>Any idea why the OVERSAMPLE_RATIO affects heavily the quality of JPEG images ?<br><br>Thanks in advance for your help,<br>Cédric<br>