Help with resizing

Hi, Whenever i try to resize and image in photoshop, i go to image size etc., for example i want a image 256x256, but when i make the top one 256, the height is totally differnt, when i change it agian same thing, how do i resize to exactly 256x256?

I don't understand what do you mean exactly. Do you hav an image that isn't square and wants it to be like that? Or you want to crop the image?

Uncheck the button that says constrain proportions.