thumbnail.aspx

transparent thumbnail generation script

<%@ Import Namespace="System" %>
<%@ Import Namespace="System.IO" %>
<%@ Import Namespace="System.Web" %>
<%@ Import Namespace="System.Drawing" %>
<%@ Import Namespace="System.Drawing.Imaging" %>
<script language="C#" runat="server">

public bool ThumbnailCallback() {
    return false;
}

private void Page_Load(object sender, System.EventArgs e) {
	int width = 600;

	string imageFile = Request.PhysicalApplicationPath + "\\" + Request.QueryString["image"].ToString();
	string thumbFile = Path.GetDirectoryName(imageFile) + "\\" +
		"thumb_" + 
		Path.ChangeExtension(Path.GetFileName(imageFile), ".jpg");
		
	System.Drawing.Image thumb;	
	
	if(!File.Exists(thumbFile) ||
		DateTime.Compare(File.GetLastWriteTime(imageFile),
					        File.GetLastWriteTime(thumbFile)) >= 0) {
		
		System.Drawing.Image img = System.Drawing.Image.FromFile(imageFile);
		int height = img.Height * width / img.Width;
		thumb = img.GetThumbnailImage(width, height, ThumbnailCallback, IntPtr.Zero);
		
		thumb.Save(thumbFile, ImageFormat.Jpeg);
	} else {
		thumb = System.Drawing.Image.FromFile(thumbFile);
	}
	
	thumb.Save(Response.OutputStream, ImageFormat.Jpeg);
}

</script>