Quote - I enter the URL and click the Insert button. That is all I did. If the width and height got populated it was Rendo's code doing it.

yes, is correct. Rendo's code is doing it.  is what happens when one clicks on the "insert img"  button.  this passes the img attributes to the forum software, which then uses height attribute whilst limiting width attribute, in case width attribute exceeds whatever maximum they've set.  now that they know your issue, they can address it.  the way I avoid it is to paste the img URL into the html editor box that one gets by clicking the "html" button on the upper left.  this prevents the forum software from wreaking havok with the aspect ratio.

p.s. the forum stylesheet contains the line

#forum_outer_table img { max-width:600px; }

editing this would only affect the usr who modifies it himself. everybody else would still see the squished img.