Bob,
If I remember correctly, you need to open the "Internet Options" once you have IE8 open.
Once you have done that, you will see a dialog box appear with a number of tabs. The tab on the right "Advanced" is the one you need to open.
Once open, scroll down the list of items with tick boxes and look for the item that asks you to keep the original image size. Make sure that it is unticked otherwise it will not adjust the image size according to you screen.
It has been a while since I used IE, as I find Safari much easier and faster to use.
Hope this helps.