I figured out you could insert an object and then double click the object to get the full size image, the only problem is the object is just displayed as an icon!
Yeah I have 2007 as well. Click on insert tab then click on object and select a .jpg file. Well, in a ghetto way you could insert the image and insert an object right beside it as a button to go full screen. I tested it and works so you don't have to supply a relative path or the image at all. Looks pretty janky though.…