Responsive passback tags can be very useful. But in order to prevent stretching, it is important to control the maximum width of the ad container. This can be done by wrapping the passback tag with a DIV (as per below).
Wrap the passback back tag in a DIV, and use an “inline” CSS style to limit the div size similar to:
In this example, we set it to limit the “container” to 400 pixels wide:
<!– original passback tag with responsive-sized ad –>
<!– passback tag begins ….
tag ends –>