以编程方式创建映像的缩略图

in my application i am getting images from the server and i am able to display the images in image view.... but now i want to store the images getting from the server in a table view and display them while clicking in the table view cell . what i want is how to make the thumbnail of the image in order to display it in table view cell .if i display the image directly in table view cell it is some what appearing clumsy.... for that i want to make the thumbnail of that image and to display it in table view cell...in my application i am getting images from the