Sorry for the late reply. Don't get me wrong, the actual page displays properly in the browsers so, I just continued with the rest of the exercises and finished the book. Again, it really is a good book.
Here is the error message for both images, that I received when I validated the XHTML. (line 12 and line 13 are on my computer, and this is from your code only)
# Line 12, Column 51: document type does not allow element "img" here; missing one of "p", "h1", "h2", "h3", "h4", "h5", "h6", "div", "address", "fieldset", "ins", "del" start-tag.
<img src='sun.png' alt='people' id='left' />
The mentioned element is not allowed to appear in the context in which you've placed it; the other mentioned elements are the only ones that are both allowed there and can contain the element mentioned. This might mean that you need a containing element, or possibly that you've forgotten to close a previous element.
One possible cause for this message is that you have attempted to put a block-level element (such as "<p>" or "<table>") inside an inline element (such as "<a>", "<span>", or "").