Image to byte array - ExternalException

Question

I'm trying to read an image from an EID with a card reader and convert it to a byte array for database storage.

Reading the image works perfectly. I'm able to retreive a valid image with these properties: enter image description here

However, I cannot convert it to a byte array. I'm using this code, although I've tried other approaches to convert it already:

public static byte[] ImageToBytes(Image image)
{
    MemoryStream stream = new MemoryStream();
    image.Save(stream, System.Drawing.Imaging.ImageFormat.Bmp);
    return stream.ToArray();

}

Calling the Save method gives following exception:

An exception of type 'System.Runtime.InteropServices.ExternalException' occurred in System.Drawing.dll but was not handled in user code

The details of the exception does not clear anything up. It's a general exception with no information about what went wrong.

Any ideas what I've been doing incorrectly?

Even when disposing the images and the stream, I'm still having this issue. Everything is checked in that list. — Bv202, Apr 03 '15 at 06:57
This may help you : http://stackoverflow.com/questions/5813633/a-generic-error-occurs-at-gdi-at-bitmap-save-after-using-savefiledialog — Nilesh Thakkar, Apr 03 '15 at 07:00
Maybe the Bitmap provided by that card reader software has some kind of dependency on something? Does the card reader software provide alternative ways of reading the image or any options that can be played with? — RenniePet, Apr 03 '15 at 07:24
No, it doesn't. I've already tried cloning the image and working on that instance already.. — Bv202, Apr 03 '15 at 07:45
Oh dear. Create a new Bitmap of the same size and copy the pixels with programming? Or display the image on the screen and take a screenshot of it? — RenniePet, Apr 03 '15 at 08:02

score 1 · Accepted Answer · edited Jun 20 '20 at 09:12

You might be using a wrong `ImageFormat`

In this documentation, it's mentioned that ExternalException will be thrown if calling .Save() with a wrong ImageFormat

you can be more generic and cover more image types if you change System.Drawing.Imaging.ImageFormat.Bmp to image.RawFormat

example:

public static byte[] ImageToBytes(Image image)
{
    MemoryStream stream = new MemoryStream();
    image.Save(stream, image.RawFormat);
    return stream.ToArray();

}

Image to byte array - ExternalException

1 Answers1

You might be using a wrong ImageFormat

You might be using a wrong `ImageFormat`