Bill, unfortunately the link does not work, it will be okay for you as you are the owner, rather than for us guests.
Not sure what application you are using for your images, but, in essence you need to resize them, most of the applications will allow you to do this and you need to select save as or save for web.
Not forgetting to save your original somewhere safe.
Changes that need to be made are resolution for web spaces, 72dpi is ample, then adjust the quality level, something around medium and the last change is the physical dimensions, the width needs to be 500 pixels. As you are doing this the actually size of the image should be shown and this will reduce as you make changes.
best of luck Peter