I think you are misunderstanding DPI. Most people correlate DPI with pixels per inch. That's not the way it works, but let's not go there. The reason your images so small is because you have the resolution set to 2400 pixels per inch. Change that to 300 pixels per inch and you should see what you are expecting.
Thank you. I am trying this now. As you can tell I am new
Pixel dimensions are what matters here - not inches.
The image is 5904 x 3048 pixels (multiply the inches with 2400 to get these numbers) , which is 18 megapixels.
So the image should be the same size as the original.
Yay! It worked. I will do my research on DPI and pixels per inch