Getting an Image object from a byte array

Question

I've got a byte array for an image (stored in the database). I want to create an Image object, create several Images of different sizes and store them back in the database (save it back to a byte array).

I'm not worried about the database part, or the resizing. But is there an easy way to load an Image object without saving the file to the file system, and then put it back in a byte array when I'm done resizing it? I'd like to do it all in memory if I can.

Something like:
Image myImage = new Image(byte[]);
or
myImage.Load(byte[]);

Answer 1

You'd use a MemoryStream to do this:

byte[] bytes;
...
using (var ms = new System.IO.MemoryStream(bytes)) {
   using(var img = Image.FromStream(ms)) {
      ...
   }
}

Answer 2

Based on your comments to another answer, you can try this for performing a transformation on an image that's stored in a byte[] then returning the result as another byte[].

public byte[] TransformImage(byte[] imageData)
{
    using(var input = new MemoryStream(imageData))
    {
        using(Image img = Image.FromStream(input))
        {
            // perform your transformations

            using(var output = new MemoryStream())
            {
                img.Save(output, ImageFormat.Bmp);

                return output.ToArray();
            }
        }
    }
}

This will allow you to pass in the byte[] stored in the database, perform whatever transformations you need to, then return a new byte[] that can be stored back in the database.

Answer 3

I thought I'd add this as an answer to make it more visible.

With saving it back to a byte array:

    public Image localImage;
    public byte[] ImageBytes;

    public FUU_Image(byte[] bytes)
    {
        using (MemoryStream ImageStream = new System.IO.MemoryStream(bytes))
        {
            localImage = Image.FromStream(ImageStream);
        }

        localImage = ResizeImage(localImage);

        using (MemoryStream ImageStreamOut = new MemoryStream())
        {
            localImage.Save(ImageStreamOut, ImageFormat.Jpeg);
            ImageBytes = ImageStreamOut.ToArray();
        }

    }