Search Image With Exact Size. Why bothering about the size. Type the width and height of the image for exact match.
Before you used to be able to do an image search then click on sizes to view things like medium and large images which are still there now. For example you could limit your search for landscape photographs to image files that were at least 12 mpx in size. That keyword will filter all the images with the precise width and height.
But you could also search for images by dimensions using the larger than option or by the exact dimensions.
In google images you can search the images with exact or certain size. One of them is image size and it lets you pick a specific minimum for your results ranging. The biggest example would be searching for exact image size. This facilitates to search by large medium or small images.