Auto Display The Images in ASP.NET (Using C#)

I have lot of pictures wih the name of:
0001.jpg 0002.jpg 0003.jpg etc
All files in One Images folder

NOW I want to create asp.net page once i put all pictures in IMAGES folder the asp.net file pick and display automatically column wise.
in 3 Colums and unlimited rows as per images.
in 1st Page should be thumbnails and once I click should come big picture in same asp.net page not open direct image.
How its possible? I did this in old asp now I want to change...

Previous old asp code if you need its with me I'll paste some of them:
<img src= <% response.write("images/B" & x.Name) %> border="0" alt="Promoton"></a></td> and

<% ctr=0 ...