Finding image in google with the exact size in very easy. When you open google webpage, you find options upper side. Click on Images and Type the item you want to search. When the page loads with images, then click on the 'Search Tools' option upside. Then click on 'Any Size' option. In this option you'll find 'Exactly' option in last in the menu. Click on it and fill the width and height in the black area, and push enter. Your exact size related images will display in the image search now. That simple.