Russ -- I further exposed ignorance by not even referring to the process with the correct terminology. So thank you for explaining the what and why. I see now that the downsizing is for illustration and comparison only -- or at least I think it is! I frequently downsize images for the paper I work for part time -- both since they don't need the total resolution and to make it easier to send photos as email attachments. This reduces 10mb jpgs to 2.5mb. So I think I grasp what is being done. I just didn't realize the other results -- maybe in my case, unintented consequences!
You and I shared some parallel tracks -- you in the AF and me in the Navy. I spent 9 years with the U.S. Army Corps of Engineers after 31 in the Navy. My last duty station though was Scott AFB in Illinois(USTRANSCOM.) I too am trying to do photography as a profession, although to date it has mostly financed acquistion of equipment. I have not finished the paper work yet, but I think I finally rolled a profit over this year! We'll see at tax time.