How can I show the thumb images (in which control) so that on click the actual image will show

Me with C# asp.net ,
In my application I want to upload images and show it as thumnail images and when clicked the thumb nail image the actual image should be shown for that

for that while uploading i had saved the image in two folders one as thumbnail and other orginal image. How can I show the thumb images (in which control) so that on click of thumb nail image the corresponding big image will show
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