Adjustable Resolution

Hi,

I need a digital camera that let me configure the resolution, lets say,
instead of taking 1024x768 pix pictures I want to take 768x768 pictures
so I dont have to worry resampling them to a prfect square later.

I dont even know what is the name of that feature -or- if that feature
exists.

THE QUESTION
Do you know some canmera models that can do this?

Thank you,

band.

.