How do I get an Icon from a png image?

Question

I'm creating an WPF app, so I'm mostly working with the ImageSource class for icons. However, the system tray icon has to be of type System.Drawing.Icon. Is it possible to create such an object from a png image?

I have tried the following:

private static System.Drawing.Icon _pngIcon;
public static System.Drawing.Icon PngIcon
{
    get
    {
        if (_pngIcon == null)
        {  
            //16x16 png image (24 bit or 32bit color)
            System.Drawing.Bitmap icon = global::BookyPresentation.Properties.Resources.star16;
            MemoryStream iconStream = new MemoryStream();
            icon.Save(iconStream, System.Drawing.Imaging.ImageFormat.Png);
            iconStream.Seek(0, SeekOrigin.Begin);
            _pngIcon = new System.Drawing.Icon(iconStream); //Throws exception
        }
        return _pngIcon;
    }
}

The Icon constructor throws an exception with the following message: "Argument 'picture' must be a picture that can be used as a Icon."

I figured it might be something with the bit depth of the image color as I had some issues with this earlier, but both 32bit and 24bit images didn't work. Is it possible what I'm trying to do?

Answer 1

You could try a small command line app called png2ico. I use it to create Windows icons from pngs.

Answer 2

Icons are a combination of 3 or 4 image sizes:

48 × 48, 32 × 32, 24 × 24 (optional), and 16 × 16 pixels.

And can/should also contain three different colour depths:

• 24-bit with 8-bit alpha (32-bit)
• 8-bit (256 colors) with 1-bit transparency
• 4-bit (16 colors) with 1-bit transparency

So the .png memory stream isn't going to fit into the icon's constructor. In fact, if you read the notes on the other constructor overloads, you'll see all the "Size" or Width and Height measurements for finding the correct size icon in the file.

More information on the manual creation of icons can be found under "Creating Windows XP Icons"

Answer 3

There is a .NET project called IconLib.

Answer 4

I think you can try something like this before convert your image to .ico:

    var bitmap = new Bitmap("Untitled.png"); // or get it from resource
    var iconHandle = bitmap.GetHicon();
    var icon = System.Drawing.Icon.FromHandle(iconHandle);

Where the icon will contain the icon which you need.

Answer 5

You can set the ImageSource of a window icon to a png image and it works, surprisingly. I haven't verified this for tray icons though.

Answer 6

There's also a website (http://www.convertico.com/) which converts PNGs into ICOs.