I have to admit I'm stumped. Looks like it should be working to me. So, you're certain the image is here: "C:\Users\MyComputer\Documents\The Tournament Director 2\Data\images\greenracetrack.gif"?
I did add a check in the Table Images dialog, to warn you if the image cannot be found. With the next beta we can at least see if the TD thinks the image exists or not.