When using the Automatic Optimize Image Option to optimize images and the Auto resize images setting is enabled, the images will be automatically resized to the dimensions they are shown onscreen. You can manually specify the size you want the images to be resized to by using the Manual Optimize Image Option .

Resize images using the Manual Optimize Image option

Simply enter the new width and height in the respective textbox beside the selected image and click the Optimize images button. The image will be resized according the specified dimensions but still maintain the aspect ratio of the original images so either the width or height may not be the exact dimension, but it would be resized for best fit.