What is the "best" way to create a thumbnail using ASP.NET? [closed]

Question

Story: The user uploads an image that will be added to a photo gallery. As part of the upload process, we need to A) store the image on the web server's hard drive and B) store a thumbnail of the image on the web server's hard drive.

"Best" here is defined as

• Relatively easy to implement, understand, and maintain
• Results in a thumbnail of reasonable quality

Performance and high-quality thumbnails are secondary.

Answer 1

GetThumbnailImage would work, but if you want a little better quality you can specify your image options for the BitMap class and save your loaded image into there. Here is some sample code:

Image photo; // your uploaded image  Bitmap bmp = new Bitmap(resizeToWidth, resizeToHeight); graphic = Graphics.FromImage(bmp); graphic.InterpolationMode = InterpolationMode.HighQualityBicubic; graphic.SmoothingMode = SmoothingMode.HighQuality; graphic.PixelOffsetMode = PixelOffsetMode.HighQuality; graphic.CompositingQuality = CompositingQuality.HighQuality; graphic.DrawImage(photo, 0, 0, resizeToWidth, resizeToHeight); imageToSave = bmp; 

This provides better quality than GetImageThumbnail would out of the box

Answer 2

I suppose your best solution would be using the GetThumbnailImage from the .NET Image class.

// Example in C#, should be quite alike in ASP.NET // Assuming filename as the uploaded file using ( Image bigImage = new Bitmap( filename ) ) {    // Algorithm simplified for purpose of example.    int height = bigImage.Height / 10;    int width = bigImage.Width / 10;     // Now create a thumbnail    using ( Image smallImage = image.GetThumbnailImage( width,                                                         height,                                                        new Image.GetThumbnailImageAbort(Abort), IntPtr.Zero) )    {       smallImage.Save("thumbnail.jpg", ImageFormat.Jpeg);    } }