<p>I have an application which I have made a 256 x 256 Windows&nbsp;Vista icon for.</p>

<p>I was wondering how I would be able to use a 256x256 PNG file in the ico file used as the application icon and show it in a picture box on a form.</p>

<p>I am using VB.NET, but answers in C# are fine. I'm thinking I may have to use reflection.</p>

<p>I am not sure if this is even possible in Windows&nbsp;XP and may need Windows&nbsp;Vista APIs</p>

Found info
here
.  To get the large Vista icon, you need to use Shell32's SHGetFileInfo method.  I've copied the relevant text below, of course you'll want to replace the filename variable with "Assembly.GetExecutingAssembly().Location".
```
```
using System.Runtime.InteropServices;
```
```
A bunch of constants we will use in the call to SHGetFileInfo() to specify the size of the icon we wish to retrieve:
```
```
// Constants that we need in the function call
private const int SHGFI_ICON = 0x100;
private const int SHGFI_SMALLICON = 0x1;
private const int SHGFI_LARGEICON = 0x0;
```
```
The SHFILEINFO structure is very important as it will be our handle to various file information, among which is the graphic icon.
```
```
// This structure will contain information about the file
public struct SHFILEINFO
{
    // Handle to the icon representing the file
    public IntPtr hIcon;
    // Index of the icon within the image list
    public int iIcon;
    // Various attributes of the file
    public uint dwAttributes;
    // Path to the file
    [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 256)]
    public string szDisplayName;
    // File type
    [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 80)]
    public string szTypeName;
};
```
```
The final preparation for the unmanaged code is to define the signature of SHGetFileInfo, which is located inside the popular Shell32.dll:
```
```
// The signature of SHGetFileInfo (located in Shell32.dll)
[DllImport("Shell32.dll")]
public static extern IntPtr SHGetFileInfo(string pszPath, uint dwFileAttributes, ref SHFILEINFO psfi, int cbFileInfo, uint uFlags);
```
```
Now that we have everything prepared, it's time to make the call to the function and display the icon that we retrieved. The object that will be retrieved is an Icon type (System.Drawing.Icon) but we want to display it in a PictureBox so we'll convert the Icon to a Bitmap using the ToBitmap() method.
But first of all there are 3 controls you need to add to the form, a Button btnExtract that has "Extract Icon" for its Text property, picIconSmall which is a PictureBox and a picIconLarge which is also a PictureBox. That's because we will get two icons sizes. Now double click btnExtract in Visual Studio's Design view and you'll get to its Click event. Inside it is the rest of the code:
```
```
private void btnExtract_Click(object sender, EventArgs e)
{
    // Will store a handle to the small icon
    IntPtr hImgSmall;
    // Will store a handle to the large icon
    IntPtr hImgLarge;

    SHFILEINFO shinfo = new SHFILEINFO();

    // Open the file that we wish to extract the icon from
    if(openFile.ShowDialog() == DialogResult.OK)
    {
        // Store the file name
        string FileName = openFile.FileName;
        // Sore the icon in this myIcon object
        System.Drawing.Icon myIcon;

        // Get a handle to the small icon
        hImgSmall = SHGetFileInfo(FileName, 0, ref shinfo, Marshal.SizeOf(shinfo), SHGFI_ICON | SHGFI_SMALLICON);
        // Get the small icon from the handle
        myIcon = System.Drawing.Icon.FromHandle(shinfo.hIcon);
        // Display the small icon
        picIconSmall.Image = myIcon.ToBitmap();

        // Get a handle to the large icon
        hImgLarge = SHGetFileInfo(FileName, 0, ref shinfo, Marshal.SizeOf(shinfo), SHGFI_ICON | SHGFI_LARGEICON);
        // Get the large icon from the handle
        myIcon = System.Drawing.Icon.FromHandle(shinfo.hIcon);
        // Display the large icon
        picIconLarge.Image = myIcon.ToBitmap();

    }
}
```
```
UPDATE: found even more info
here
.