' normalthumbnail.vb ' Image.FromFileメソッド+GetThumbnailImageメソッドによる作成 Imports System Imports System.IO Imports System.Drawing Imports System.Diagnostics Class CreateThumbnailTest Shared Function dummy() As Boolean Return False End Function Shared Sub Main() Dim dir As String = "C:\jpgs" ' 画像のあるディレクトリ Dim jpgFiles As String() = Directory.GetFiles(dir, "*.jpg") Dim sw As Stopwatch = Stopwatch.StartNew() For Each jpg As String In jpgFiles Console.WriteLine(jpg) ' 画像オブジェクトの作成 Dim orig As Image = Image.FromFile(jpg) ' サムネイルの作成 Dim thumbnail As Image = orig.GetThumbnailImage(160, 120, _ New Image.GetThumbnailImageAbort(AddressOf dummy), IntPtr.Zero) ' サムネイルの保存 thumbnail.Save("tn_" + Path.GetFileName(jpg), _ System.Drawing.Imaging.ImageFormat.Jpeg) orig.Dispose() thumbnail.Dispose() Next sw.Stop() Console.WriteLine(sw.ElapsedMilliseconds & "ミリ秒") ' 出力例:53109ミリ秒 End Sub End Class ' コンパイル方法:vbc normalthumbnail.vb