C# - Parameter Is Not Valid Calling Bitmap.Save()?

This in in an ASP.NET application.

Locally, this code runs fine, but on our production server, it throws an exception of 'Parameter is not valid' when Bitmap.Save() is called.

Should I not be using System.Drawing.Bitmap because its not recommened based on this:

[URL]

Classes within the System.Drawing namespace are not supported for use within a Windows or ASP.NET service. Attempting to use these classes from within one of these application types may produce unexpected problems, such as diminished service performance and run-time exceptions.

What else could I use?

Bitmap myBitmap = new Bitmap(img);
myBitmap.SetResolution(img.HorizontalResolution, img.VerticalResolution);
// get the tiff codec info
ImageCodecInfo myImageCodecInfo = GetEncoderInfo("image/tiff");
// Create an Encoder object based on the GUID for the Compression parameter category
System.Drawing.Imaging.Encoder myEncoder = System.Drawing.Imaging.Encoder.Compression;
// create encode parameters
EncoderParameters myEncoderParameters = new EncoderParameters(1);
EncoderParameter myEncoderParameter = new EncoderParameter(myEncoder, (long)EncoderValue.CompressionCCITT4);
myEncoderParameters.Param[0] = myEncoderParameter;
// save as a tiff
myBitmap.Save(input, myImageCodecInfo, myEncoderParameters);