You set image resolution using the controls in the Resolution control group. These controls are disabled unless the file being saved is an image format and screen capture is not being used. You specify the image height and width by typing new values into the Height and Width text fields. If the Maintain 1:1 aspect check box is on, VisIt forces the image's height and width to be the same, yielding a square image. Turn off this setting if you want to save rectangular images. The image resolution is ignored unless you turn off the Screen capture check box.