The Image-Sizer is a "HISTORY TOOL"; It looks FOR the image that you JUST finished looking AT. To use The Image-Sizer you must come to it DIRECTLY From The Image You Wish To View. You must save the tool page on one of your "F-Keys" (f-1 ~ f-7). Hit your F-Key while you are looking at the image you want to size. When you arrive at the tool you will see the image rather than the Empty Square Box