Invalid parameter error when calling System.Drawing.Image.Save

Question

I get an Invalid Parameter error when calling the System.Drawing.Image.Save function. i google and found some suggestions but nothing works. what I'm trying to do is that when I upload an image, and if it is lager than 100kb, I would like to reduce the image size to half. please, help.

System.Drawing.Image FullsizeImage = System.Drawing.Image.FromFile(realpath); FullsizeImage = System.Drawing.Image.FromFile(realpath); int fileSize = (int)new System.IO.FileInfo(realpath).Length; while (fileSize > 100000) //If Larger than 100KB { SaveJpeg(realpath, FullsizeImage); fileSize = (int)new System.IO.FileInfo(realpath).Length; } private static ImageCodecInfo GetEncoderInfo(string mimeType) { // Get image codecs for all image formats ImageCodecInfo[] codecs = ImageCodecInfo.GetImageEncoders(); // Find the correct image codec for (int i = 0; i < codecs.Length; i++) if (codecs[i].MimeType == mimeType) return codecs[i]; return null; } public static void SaveJpeg(string path, Image img) { Image NewImage = img; img.Dispose(); EncoderParameter qualityParam = new EncoderParameter(Encoder.Quality, 85L); EncoderParameters encoderParams = new EncoderParameters(1); encoderParams.Param[0] = qualityParam; ImageCodecInfo jpegCodec = GetEncoderInfo(GetMimeType(path.Substring(path.LastIndexOf('.'), path.Length - path.LastIndexOf('.')))); //THE ERROR IS HERE!!!!!! NewImage.Save(path, jpegCodec, encoderParams); //THE ERROR IS HERE!!!!!! } public static string GetMimeType(string extension) { if (extension == null) { throw new ArgumentNullException("extension"); } if (!extension.StartsWith(".")) { extension = "." + extension; } switch (extension.ToLower()) { #region Big freaking list of mime types // combination of values from Windows 7 Registry and // from C:\Windows\System32\inetsrv\config\applicationHost.config // some added, including .7z and .dat case ".323": return "text/h323"; // more extension here.. #endregion default: // if you have logging, log: "No mime type is registered for extension: " + extension); return "application/octet-stream"; } } 

EDIT: I changed the code as shown below, now the image is saved without any exceptions! Thank you but another problem here. file size is not reduced. which means my while loop can never exit. please help and thanks again.

 using (MemoryStream ms = new MemoryStream(File.ReadAllBytes(realpath))) { using (Image FullsizeImage = Image.FromStream(ms)) { //code here int fileSize = (int)new System.IO.FileInfo(realpath).Length; while (fileSize > 100000) //If Larger than 100KB { SaveJpeg(realpath, FullsizeImage, 85L); fileSize = (int)new System.IO.FileInfo(realpath).Length; } } } 

Can someone help me, my problem is not solved yet :(

Answer 1

Since you are removing the image object.

 public static void SaveJpeg(string path, Image img) { Image NewImage = img; img.Dispose(); <------- Here ... } 

EDIT: The Image.FromFile method of a file opens a stream, and this file will not be closed until your method is complete. Try using a MemoryStream.

 using (MemoryStream ms = new MemoryStream(File.ReadAllBytes(realPath))) { using (Image img = Image.FromStream(ms)) { ImageCodecInfo myImageCodecInfo; Encoder myEncoder; EncoderParameter myEncoderParameter; EncoderParameters myEncoderParameters; myImageCodecInfo = GetEncoderInfo("image/jpeg"); myEncoder = Encoder.Quality; myEncoderParameters = new EncoderParameters(1); myEncoderParameter = new EncoderParameter(myEncoder, 85L); myEncoderParameters.Param[0] = myEncoderParameter; img.Save(realPath, myImageCodecInfo, myEncoderParameters); } }