Resizing Images and getting a black background and larger file size

I am using asp.net to upload an image and then perform resizing on it and
saving the different sizes to file.
The resized images were coming up and being displayed in the bowser fine but
the image sizes are a lot bigger(in file size) than the actual image being
uploaded.
The actual image being uploaded was around 22000bytes
The smaller resized image is 120000bytes

Also on the web when the resized image is displayed it starts out with a
black background and progressivly shows the image


I also downloaded some of the resized images and tried opening them in
photoshop and I got an error saying it couldn't open them because of an
unknown jpeg marker.
I posted my code for resizing the image below, mabey I went about it wrong.
Any ideas



-------------------------------------------------------

this.CreateSpecialRotator(ImageName,"SpecialProduc ts",180,180);



private void CreateSpecialRotator(string ImageName,string DirectoryName,int
Width, int Height)
{
if(! System.IO.Directory.Exists(this.ImageUploadDirecto ryPath + "\\" +
DirectoryName))
{
System.IO.Directory.CreateDirectory(this.ImageUplo adDirectoryPath +
"\\" + DirectoryName);
}

if(File.Exists(this.ImageUploadDirectoryPath + "\\" + ImageName))
{
System.Drawing.Image i =
System.Drawing.Image.FromFile(this.ImageUploadDire ctoryPath + "\\" +
ImageName);
System.Drawing.Bitmap ThumbNail;

if(i.Width > 180)
{
ThumbNail = new
Bitmap(i,180,this.CalculateHeight(i.Height,i.Width ,180));
}
else
{
ThumbNail = new Bitmap(i);
}
ThumbNail.Save(this.ImageUploadDirectoryPath + "\\" + DirectoryName
+ "\\" + ImageName);
i.Dispose();
ThumbNail.Dispose();
}
}

Thanks,
Ron Vecchi

re: Resizing Images and getting a black background and larger file size

Hi Ron,

You may try to sepcify the image's format property when saving it, for
exmaple:

ThumbNail.Save("c:\test\result.jpg",
System.Drawing.Imaging.ImageFormat.Jpeg);

Based on my test, the result jpg file will be smaller than source file with
above code.

Hope this help,

Luke
Microsoft Online Support

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