The resize feature allows you to resize an image in a variety of different ways. To resize an image, enter the desired width and height, in pixels or in percent, then click save.
When resizing, check the box that says "Maintain Aspect Ratio" to keep the aspect between the width and height the same as the original image. Unchecking this box allows you to enter any width and height, regardless of the aspect of the original file. Unchecking "Maintain Aspect Ratio" also lets you choose from the Resize Style. There are two styles: Stretch: Pulls/pushes the width and height of the image to match the width and height you specified. Matte: Creates a new image using the background color you specify, and places the original image in the center in the largest area it can fill.