OK I seem to have found the cause just by sheer luck and its nothing wrong with that particular method, it’s further back up the call stack.
Earlier I resize the image and as part of that method I return the resized object as follows. I have inserted two calls to the above method and a direct save to a file.
// At this point the new bitmap has no MimeType
// Need to output to memory stream
using (var m = new MemoryStream())
{
dst.Save(m, format);
var img = Image.FromStream(m);
//TEST
img.Save(“C:\test.jpg”);
var bytes = PhotoEditor.ConvertImageToByteArray(img);
return img;
}
It appears that the memory stream that the object was created on has to be open at the time the object is saved. I am not sure why this is. Is anyone able to enlighten me and how I can get around this.
I only return from a stream because after using the resize code similar to this the destination file has an unknown mime type (img.RawFormat.Guid) and Id like the Mime type to be correct on all image objects as it makes it hard write generic handling code otherwise.
EDIT
This didn’t come up in my initial search but here’s the answer from Jon Skeet
If you are getting that error , then I can say that your application doesn’t have a write permission on some directory.
For example, if you are trying to save the Image from the memory stream to the file system , you may get that error.
Please if you are using XP, make sure to add write permission for the aspnet account on that folder.
If you are using windows server (2003,2008) or Vista, make sure that add write permission for the Network service account.
Hope it help some one.