This thread is for discussions of Dynamic thumbnail images from ASP.NET.

The easiest way to upload and resize an image to the internet is I-Load.
This component also create  an unlimited number of thumbnails  from the original image with the required size.
I-Load is a FREE ASP.NET web control with numerous benefits and features.
You can download I-Load (it's FREE!) and view an online demo here:

http://www.radactive.com/en/Products/ILoad/Overview.aspx

Wow, unbeatable!

Check out its numerous benefits and features:

- Uploads images without writing even one line of code
- Informs the user of the status of the uploading process
- Allows either automatic or manual resizing and cutting of the uploaded image
- Automatically generates unlimited resizing options from the original image
- Allows previews of the uploaded images
- Integrates perfectly with the Microsoft Visual Studio .NET environment

That's what I needed for my photo gallery! Thanks a lot guys.

Take a look at their beta version ... ***I-Load 1.5 Beta ***

The framework documentation at http://msdn2.microsoft.com/en-us/library/system.drawing.aspx states that "Classes within the System.Drawing namespace are not supported for use within a Windows or ASP.NET service. Attempting to use these classes from within one of these application types may produce unexpected problems, such as diminished service performance and run-time exceptions."

We have verified that its use crashes asp.net worker processes.

THIS IS THE WRONG WAY TO DO THIS - at least, in most cases.

If you call the GetThumbnailImage() method, as stated in the documentation, it will return the thumbnail image EMBEDDED IN THE IMAGE resized to the size you requested.

In many cases, this isn't what you want. For example, let's say I take a photo from my Minolta 7D, it is 2000x3006 pixels, with an 100x150 embedded thumbnail.

I now request a "thumbnail" image that is 400x600.  It will take the 100x150 image and blow it up to be 400x600.  It will not take the large image and scale it.

To do that, you need to create another image, and draw the large image on to it and save the new image.

The only case where this will work is if the image you want is smaller than the one that is embedded, or if there is no embedded image.  If you are using this generically, then you need to consider someone uploading a 2K x 3K image with a 16x16 embedded thumbnail.. Not pretty when you blow it up to 100x150 or whatever.

If you want to confirm this problem, just blow up an image to the original size using this method.  Depending on the make of the camera you used to get the image, it will either look good or look like crud.

Chert
www.traderhut.com