Image data loss when converting to byte array

Question

I'm trying to use a MemoryStream to turn an image into a byte array, however, the image looks different when I recover it.

I made a simple Form app to show the issue. I'm using the google chrome Icon for this example:

var process = Process.GetProcessById(3876); // found pid manually
var image = Icon.ExtractAssociatedIcon(process.MainModule.FileName).ToBitmap();
pictureBox1.Image = image;

byte[] imageBytes;
using (var ms = new MemoryStream())
{
    image.Save(ms, ImageFormat.Bmp);
    imageBytes = ms.ToArray();
}

using (var ms = new MemoryStream(imageBytes))
{
    pictureBox2.Image = (Bitmap) Image.FromStream(ms);
}

Result:

Any idea what I'm missing here?

Update I was able to get the proper bytes using the following code:

var converter = new ImageConverter();
var imageBytes = (byte[]) converter.ConvertTo(image, typeof(byte[]));

Would still like to know whats up with the Memory stream though..

Try to use the 32bit format like PNG. The circle needs probably transparency. — user6522773
– user6522773, Commented Jul 6, 2016 at 0:01

Community · Accepted Answer · 2017-05-23 12:16:38Z

3

Icons are complicated. When they contain transparent parts, converting to BMP or JPG almost always seems to end badly. You also dont need ImageConverter it is doing almost what your code does without the BMP conversion:

var process = Process.GetProcessById(844); // found pid manually
var image = Icon.ExtractAssociatedIcon(process.MainModule.FileName).ToBitmap();
pb1.Image = image;

byte[] imageBytes; 

using (var ms = new MemoryStream())
{ 
    image.Save(ms, ImageFormat.Png);        // PNG for transparency
    ms.Position = 0;
    pb2.Image = (Bitmap)Image.FromStream(ms);                
}

ImageConverter Reference Source

edited May 23, 2017 at 12:16

CommunityBot

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answered Jul 6, 2016 at 0:56

Ňɏssa Pøngjǣrdenlarp

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