gdi+ - ASP.NET convert image from PNG to jpg -

i having problem converting image png jpg. jpg jpg png jpg having pixelated problem. i've implemented compression method code still couldn't produce high quality image.

any ideas guys?

using system; using system.collections.generic; using system.web; using system.web.ui; using system.web.ui.webcontrols; using system.drawing.imaging; using system.drawing; using system.io; using system.drawing.drawing2d; public partial class _default : system.web.ui.page {      private imagecodecinfo getencoder(imageformat format)     {         imagecodecinfo[] codecs = imagecodecinfo.getimagedecoders();         foreach (imagecodecinfo codec in codecs)         {             if (codec.formatid == format.guid)             {                 return codec;             }         }         return null;     }      protected void page_load(object sender, eventargs e)     {         response.contenttype = "image/jpeg";//convert tojpeg web usage          // bitmap.         bitmap bmp1 = new bitmap(@"e:\websites\logomaster\logoid4.png");         imagecodecinfo jgpencoder = getencoder(imageformat.jpeg);         // create encoder object based on guid         // quality parameter category.         system.drawing.imaging.encoder myencoder =system.drawing.imaging.encoder.quality;         // create encoderparameters object.         // encoderparameters object has array of encoderparameter         // objects. in case, there 1         // encoderparameter object in array.         encoderparameters myencoderparameters = new encoderparameters(1);         encoderparameter myencoderparameter = new encoderparameter(myencoder, 100l);//set highest quality         myencoderparameters.param[0] = myencoderparameter;        // bmp1.save(@"e:\websites\logomaster\testphotoqualityhundredp.jpg", jgpencoder, myencoderparameters);         bmp1.save(response.outputstream, jgpencoder, myencoderparameters);         bmp1.dispose();      }  } 

maybe need redraw image? answered question on generating thumbnails (asp.net version of timthumb php class) made images nice , clean.

            dim bmpthumb new bitmap(destwidth, destheight)             dim g = graphics.fromimage(bmpthumb)             g.interpolationmode = drawing2d.interpolationmode.highqualitybicubic             g.compositingquality = drawing2d.compositingquality.highquality             g.smoothingmode = drawing2d.smoothingmode.antialias              g.drawimage(img, _                         new rectangle(0, 0, destwidth, destheight), _                         new rectangle(sourcex, sourcey, sourcewidth, sourceheight), graphicsunit.pixel)              '-----write out thumbnail output stream------'                     'get jpeg image coded info can use when saving'             dim ici imaging.imagecodecinfo = imaging.imagecodecinfo.getimageencoders().where(function(c) c.mimetype = "image/jpeg").first()              'save image memory stream'             dim ms new memorystream()             bmpthumb.save(ms, ici, buildqualityparams(context)) 

once save memory stream need write out asp.net response stream:

         context.response.clear()             context.response.contenttype = "image/jpeg"             ms.writeto(context.response.outputstream)             context.response.flush()