Image objects

Hi,

i am currently giving a look to OpenCL. I just wanted to ask a question regarding image objects. In OpenCL, one can allocate memory on the devices accessible to kernerls.
Ok. What is the purpose of Image objects? I mean, i can create a normal buffer object, put my image there, pass the width and height as parameters to the kernel.

Thx.

Instead of doing a simple array lookup, you can sample individual pixels controlled by certain parameters such as address clamping and interpolation mode. On GPU hardware this is going to be a lot faster than doing it manually.