''' <summary>
''' Sets the creation time of PNG file.
''' </summary>
''' <param name="filename">The filename.</param>
''' <param name="creationDate">The creation date of file.</param>
Public Shared Sub SetCreationTime(filename As String, creationDate As System.DateTime)
    ' open PNG file
    Using pngFile As New Vintasoft.Imaging.Codecs.ImageFiles.Png.PngFile(filename)
        Dim page As Vintasoft.Imaging.Codecs.ImageFiles.Png.PngPage = pngFile.Page

        ' get the textual information of image
        Dim textualInformation As System.Collections.Generic.Dictionary(Of String, String) = page.GetTextualInformation()

        ' add the creation date to the textual information
        textualInformation("Creation Time") = creationDate.ToString("yyyy:MM:dd hh:mm:ss", System.Globalization.CultureInfo.InvariantCulture)
        ' set textual information of image
        page.SetTextualInformation(textualInformation)

        ' save changes in PNG file
        pngFile.SaveChanges()
    End Using
End Sub

/// <summary>
/// Sets the creation time of PNG file.
/// </summary>
/// <param name="filename">The filename.</param>
/// <param name="creationDate">The creation date of file.</param>
public static void SetCreationTime(string filename, System.DateTime creationDate)
{
    // open PNG file
    using (Vintasoft.Imaging.Codecs.ImageFiles.Png.PngFile pngFile = 
        new Vintasoft.Imaging.Codecs.ImageFiles.Png.PngFile(filename))
    {
        Vintasoft.Imaging.Codecs.ImageFiles.Png.PngPage page = pngFile.Page;

        // get the textual information of image
        System.Collections.Generic.Dictionary<string, string> textualInformation = page.GetTextualInformation();
        
        // add the creation date to the textual information
        textualInformation["Creation Time"] = creationDate.ToString("yyyy:MM:dd hh:mm:ss", 
            System.Globalization.CultureInfo.InvariantCulture);
        // set textual information of image
        page.SetTextualInformation(textualInformation);

        // save changes in PNG file
        pngFile.SaveChanges();
    }
}