Solved with this code from support, thanks!
<!--[if lte IE 9]>
<s-tyle type="text/css">
div.main-image img.product-image { max-width:130px; }
</style>
<![endif]-->
"Copy-paste the above lines to this PHP file:
templates/*******template name******/index.php
(within the <head>...</head>)
That IF condition <!-- [if lte IE 9]> checks IF the browser is equal or lower than 9, (so it includes IE8 and IE7 as well, but excludes IE10)
I hope this will work better in your case. Eventhough the "enlarge functionality" won't work in IE9 and IE8, it will be working in all other browsers. Assume only 10%-15% users still using IE9 nowadays, you still have 85% to show the "enlarge functionality" ;)
Regards.
Support."