Here are my settings for www.tihaskennels.com  (below) 

Obviously, the picture on the website at this moment is not the same picture below but I am having issues on how to know what size I need to make the picture to look similar to that.  I am blind guessing at this moment and was wondering if ya'll could help me figure it out. I have the picture (I will need to photoshop more background because the image is a tad small) but All my measurements are coming up wrong. How do I find out what size to make the gray/white dog background picture