Very right... Was definitely overthinking the method and underestimating the ability of the good old table properties. You guys are great - thanks for the input!
The border style properties need to be set right.
The properties work as "border-left: *width, style, color"
border-left: 1px (width) solid (style) #FFF (color);
Make sure to leave the semi-colon out between the properties.
Adding the max-width inline could help.
<img src="http://www..." width="640" style="width: 100%; max-width: 640px; height: auto; ms-interpolation-mode: bicubic; ">
Omit the px on the height and width attributes but not within the style.
Hoping this does the trick for you.