C#

CPallini wrote:

the function's name, 'ReadFile', is so obscure

Eddy Vluggen wrote:

That is called research. It's an inevitable part of development

Image image = Image.FromFile(@"c:\logo.png");
Bitmap buffer = new Bitmap(image.Width, image.Height);
buffer.SetResolution(image.HorizontalResolution,image.VerticalResolution);

Rectangle destRect = new Rectangle(0, 0, image.Width, image.Height);

ImageAttributes attributes = new ImageAttributes();

// Set the transparent color 
attributes.SetColorKey(Color.Red, Color.Red);

using (Graphics gr = Graphics.FromImage(buffer)) {
    gr.DrawImage(image, destRect, 0, 0, image.Width,
                image.Height, GraphicsUnit.Pixel, attributes);
}

buffer.Save(@"c:\logo2.png");

Naveed khan nido wrote:

I want to make transparent whole image

Image img = Image.FromFile(@"c:\logo.png");
Bitmap buffer = new Bitmap(img.Width, img.Height);
buffer.SetResolution(img.HorizontalResolution, img.VerticalResolution);
buffer.Save(@"c:\logo2.png");